It shrinks longer links in order to make them more tweetable (and retweetable), it gives you some options to share links from its main website, throws in some analytics so you can see just how few people actually click those links you’re spreading and comes with an API.

The only slight advantage it could have over competitors like TinyURL and bit.ly is a tight integration with the TweetMeme service / button, but they won’t be exploiting that connection and keep on supporting the URL shortening services as they were before (which is obviously the right thing to do).

TweetMeme founder Nick Halstead asks the appropriate question in the e-mail announcing ReTwt.me: why did they build this? The answer:

Firstly and foremost ‘reliability’, we pride ourselves at TweetMeme for the continued up-time and scalability of the service. Going forward we wanted to have ‘platform security’ that we always had a fallback position if any of the current shorteners either closed down or had any outages.

I have my doubts about ReTwt.me being more serious about uptime and scalability than some of the other services, like bit.ly (a venture-capital funded startup to which URL shortening and analytics is core business) and Digg (which I’m sure has a lot more load on its servers than TweetMeme currently has), but having a fall-back option I guess makes sense.

Nevertheless, I can’t imagine why any end user would want to switch to ReTwt.me for URL shortening purposes. Halstead bets on the simpleness of the service, but I don’t know how anyone could make the existing URL shortening services more basic than they already are.

But please do judge for yourself (and don’t forget to retwt this story).

When it comes to shortening links, the brevity of the URL is not the only factor you should consider. Speed and reliability are also important. After all, the main purpose of URL shortening services such as bit.ly and TinyURL are to redirect you back to the original (long) link someone shortened in the first place. You want the redirect to be fast and reliable.

The rise of Twitter and its character constraints has made URL shortening services popular. But which one is the best? Royal Pingdom decided to conduct a test over the past 30 days to put nine of URL shortening services through the paces. Overall, Ow.ly and Bit.ly came out on top, while Tr.im came in dead last (no wonder nobody would buy it).

Pingdom tested two things: the average time it took each service to load a page (overhead) and its uptime. The fastest service was actually Is.gd (with an average load time of 163 milliseconds), followed by bit.ly (261 milliseconds) and ow.ly (289 milliseconds).

Tr.im was the third slowest after Cli.gs and Snip.url. But when it comes to reliability, Tr.im had nearly twice the estimated yearly downtime as the next worse service (Twurl). Even with nearly 80 hours of estimated annual downtime, Tr.im still had 99.10 percent reliability. Ow.ly, however, had 100% uptime, and bit.ly came in second with 99.98 percent. (Is.gd came in fifth).

When both the reliability and speed rankings are combined, ow.ly and bit.ly tie for first place overall, followed by Is.gd and Su.pr. Here is the complete ranking (the scores are the rankings for each test added together):

Overall Ranking

• Ow.ly: 2
• Bit.ly: 2
• Is.gd: 3
• Su.pr: 3.5
• TinyURL: 4.5
• Twurl: 7
• Snipurl: 7.5
• Cli.gs: 7.5
• Tr.im: 8.5

To get this implemented, Twitter went with TinyURL, a service that shortens URLs down signficantly (but not extremely) and at the time had been around for years already. It never gave a reason for this choice, but it did provide TinyURL with a lot of exposure and a lot of extra traffic.

Those days are over. Apparently, Twitter has silently replaced TinyURL as its default URL shortening service with bit.ly, a competing service that launched quite recently and not too long ago raised $2 million from several prominent angel investors.

This is actually not that much of a surprise. Betaworks, the startup accelerator behind Twitter related companies such as Summize (acquired by Twitter in July 2008), is also behind bit.ly, and it just happens to also count early Twitter investors and advisors Chris Sacca and Ron Conway as their own backers.

Which obviously prompts this inevatible question: does the move signal Twitter paving the way for an outright acquisition of the URL shortening service provider?

(Thanks to Avi Muchnick for letting us know)

Update: shame on me for forgetting that TechCrunch also has its ‘own’ short URL (tcrn.ch), which you can view under every post and which we use for our Twitter account. We use awe.sm for this.

The latest startup to add a URL shortening feature to its service is UnHub, which we covered last month. Paste any URL after unhub.com and if you’re registered for the service, you’ll get a custom short URL you can use to distribute links to articles and such. On top of the linked website will be an iframe (yes, yet another one) where you can view the number of Diggs, bookmarks on Delicious, and redirects on bit.ly. You can also tweet, e-mail or share the link on a plethora of third-party services right from the toolbar. It’s also personalized, so people can jump to your own UnHub profile from the persistent bar, or straight to the source link. For an example, go to http://unhub.com/pC16.

Another one that just surfaced (in alpha mode) is Lnk.by, which adds a twist to URL shortening in the sense that you can pick a short URL that suits what you’re linking to i.e. it brings some context to what you’re sharing. You can share music files using Lstn.in, videos with Wach.it, photos with Seee.it and articles with Read.im. The service automatically maps known domains, protocols and file extensions so it will pick the most suitable one without the need for indicating it proactively. Other than that, there’s nothing really noteworthy about the service, apart from the fact it comes with an API and a toolbar bookmarklet, and that it was built by an Endemol executive with a friend in just one weekend.

Feel to shorten the URL for this article with both services and tell us which one you prefer (or why you hate URL shortening services).

One of the most viral activities on the Web is sharing links. It is fast and easy, and a good way to communicate ideas. What started out as something people did via e-mail and bookmark-sharing services like Delicious, is now moving to Facebook, Twitter, and other social broadcasting services. It is just so much more efficient to share a link once with all your friends and followers than to send it to each one individually.

Twitter is especially suited to sharing quick links, but its 140-character limit has perhaps done more than anything else to propel forward the use of URL shorteners. These take long URLs and turn them into shorter ones that usually redirect people back to the original. So for instance, http://www.techcrunch.com/2009/04/06/revolution-money-raises-another-42-million-for-alternative-payment-service-nobody-is-using/ becomes http://tinyurl.com/coflho or http://bit.ly/q3Sl9 or http://digg.com/u1LRR.

There are more than a dozen such services, including TinyURL, bit.ly, Snurl, tr.im, is.gd, and the new Diggbar. The better ones offer tracking stats. One of them, bit.ly, just raised $2 million. Nobody really likes them, but they are a necessary evil. How else are you going to share links on Twitter without having the URL take up half the message?

It may be more complicated than that, however. Joshua Schachter, the founder of Delicious, thinks they are downright evil. Schachter writes, “The worst problem is that shortening services add another layer of indirection to an already creaky system.” In other words, they slow down the Web. He gives several other reasons why they are bad as well. They add a whole new slew of middlemen to the equation, and these links become dependent on the continued existence of these startups or even the whimsical changes in their terms of service. URL shorteners make links opaque, which spammers love.

They also add an unnecessary extra step to what should be a fairly simple message. Some, like Digg’s new Diggbar, also steal link juice from the original destination by wrapping the Website in a frame rather than redirecting to it. That just messes with the whole link structure of the Web. If I am linking to your story using a shortened Digg URL, Digg gets the credit, not your Website. Most URL shorteners don’t do this, but If Digg is successful with its new feature, they may follow suit. If that becomes an accepted practice on the Web, it would create all sorts of complications for the search engines in terms of duplication and making sure the underlying link gets the proper ranking.

There is a simple solution to all of this. Services like Twitter could simply do a better job of incorporating links into their design by allowing users to hyperlink existing words in their messages, without wasting space by displaying the actual URL. This is how FriendFeed handles the issue. Or it could carve out a separate place for links outside the message (perhaps through a “link” button at the bottom of each Tweet). The only reason to keep the URL within the message itself is for SMS messages, and for those perhaps Twitter would be better off creating its own URL shortening service that can become the standard, or buy one of the existing ones. If it ever does go the acquisition route, bit.ly might be a leading candidate. It was created by Betaworks, the main investor behind the startup Twitter purchased last year (Summize) when it realized it needed its own real-time search engine.

So are URL shorteners necessary or just evil?

Are URL shorteners evil?
( online surveys)

In a world where everything is being jammed into 140 characters or less, shorter is better. That goes double (or is it half?) for lengthy URLs. So-called URL shortening services are increasingly becoming indispensable to anyone who uses Twitter. It is the only practical way to share links on the service.

Today, one of these URL shortening services, bit.ly, raised $2 million, sparking the question: How much are these things actually worth? Nobody really knows.

But here is some fun math. Assuming bit.ly sold 20 percent of its shares to its new investors (the O’Reilly Alpha Tech Fund, Mitch Kapor, and Howard Lindzon), that would imply an $8 million pre-money valuation ($10 million post-money). Its market share of shortened links, as calculated by Tweetmeme, is only 13 percent. The biggest URL shortner out there is actually TinyURL, which commands a 75 percent share. So by that metric, if bit.ly is worth $8 million, TinyURL should be worth at least $46 million (8/13 X 75 = 46.15). Yes, I am making up these numbers, just like the investors do.

But wait. Bit.ly seems to be shooting up like a rocket, while TinyURL may have plateaued. Why is bit.ly growing so much faster? One big reason is because it creates even shorter URLs than TinyURL does by about five characters (http://bit.ly/ versus http://tinyurl.com/). Don’t laugh. Every character counts. Bit.ly also offers better analytics and tracking tools on the backend.

Don’t get too caught up in the site traffic growth figures either, though. Traffic to http://bit.ly/ and http://tinyurl.com/ cannot be trusted as reliable proxies for usage because heavy users don’t go to the corresponding websites. They use desktop clients or browser based tools instead which incorporate one service or the other. For instance, TweetDeck (a popular Twitter client) uses bit.ly as its default shortener. The bit.ly service itself is a spin-off from Betaworks, which is also an investor in Tweetdeck (and in Twitter). See how it works?

How any URL shortener is supposed to make money is still unclear. The links themselves act as pass-throughs to the original sites. TinyURL has slapped some Google ads on its site and bit.ly doesn’t even bother. The data each service is collecting might be valuable and could be packaged in various ways to brand marketers or other corporate buyers . . . perhaps. Or more likely, these things become features of other services.

Already Digg is working on its own URL-shortening toolbar wrapped into its service, and Stumbleupon is working on su.pr, which is even shorter than bit.ly!

A super-secret Digg toolbar has been spotted in the wild. We tracked down a beta tester who gave us the skinny on its features. The toolbar lets you Digg or Bury the page you are on, and shows how many Diggs it has already received. There are also links to show related pages, as well as more pages from the same source voted highly by the Digg community or marked as up and coming.

Then there is the “Random” button which works like StumbleUpon. It takes you to a randomly-generated page based on your past input and overall Digg voting. By the prominence of this button, it appears that is a feature Digg will be trying to highlight. Users can also share the page via Facebook, Twitter, or email via icons at the top. A drawer slides down to expose additional functionality.

Now, here where it gets interesting. For each page, the toolbar creates a shortened URL similar to TinyURL or bit.ly that starts instead with http://digg.com/. . . followed by a six-character code such as “http://digg.com/d1gVha.” When you share a page via Twitter or Facebook, it is that shortened URL which is used. And in fact, for the beta testers, the toolbar can be wrapped around any page simply by sticking “http://digg.com/” in front of any URL, which then gets converted into a shortened version. This technique works for pages that have never been Dugg as well. I could see this feature eventually showing up as part of a browser add-on so that Digg URL’s could be created with one click.

The toolbar is not an add-on to existing browsers. It is actually creating a large i-frame around the original Webpage and delivering it on the Digg.com domain. Users can click on an X to get rid of the toolbar frame and be taken to the original page, and the original page gets the hit as well. (This is a similar technique to what Ginx does with its Web-sharing Twitter client). But by running all of the recommended pages through its own domain, Digg can run all sorts of analytics on each page such as how many people viewed it, where people clicked to next, and so on.

It is amazing that Twitter has single-handedly created this need for shortened URLs and that a relatively large player like Digg now wants a piece of that market.

Click on the screenshot below for a larger image:

TinyURL is the place to go if you have a long URL that you want to cut down for friends, but if you’re looking for a way to easily send Google search results to them without picking a specific page, Look.fo lets you send them an exact link to your query in a simple style: look.fo/your search query.

I had the opportunity to try out Look.fo and it works as advertised. The page’s design is simple and contains a search box that lets you input your query. Once you do, a vanity URL is created so you can copy it and send it along. You can also search on the Look.fo site by inputting your query, which then brings you Google search results.

I tried Look.fo out with something easy like “TechCrunch” and the site performed well. It quickly formed the URL (http://look.fo/techcrunch) and the Google search results it returned were what you’d expect—accurate enough for me to justify sending that to someone who wants to know more about TechCrunch.

To test it out a bit further, I tried a more advanced query to see how the URL was formed. At this point, I tried “introducing a puppy to a dog in your home.” Once again, the URL (http://look.fo/introducing-a-puppy-to-a-dog-in-your-home) was formed on-the-fly and the search results exactly matched what you can find on Google.com. (Again, as you’d expect, since Look.fo is powered by Google custom search).

Look.fo says it’s a solution designed specifically for those that want to send others search queries and could be an ideal research tool for Universities. I tend to agree on both counts. It may be simple and you can theoretically do this already with other services like TinyURL, but Look.fo makes takes out a step. It is perfect for Twitters, SMS messages, or mobile email, where brevity is essential.

Some technologies take things down a notch. For instance TinyPaste, a service obviously built with Twitter in mind that lets you link to ramblings in excess of the regular 140 character limit.

Just like TinyURL and other URL shortening services, TinyPaste produces a short address that you can enter into microblogging and IM services with caps on message lengths. But instead of directing users to a regular webpage, a TinyPaste’s URL sends its clickers to a simple page displaying the poster’s message.

Who would use this? Perhaps those who don’t maintain blogs but who still want to expound on their thoughts from time to time. It’s common practice for bloggers to adopt Twitter as a marketing tool that drives traffic back to their sites. This could start a reverse trend of sorts, one that introduces tweeters to the art of blogging. Or maybe I’m just extracting too much.

In any case, TinyPaste also comes with a Firefox extension for when you want to pass along a clip of text you found on the web. The service and plugin come from the same guys who brought you ControlC.