Bookmarking and tagging websites can be a messy business. Zigtag, a new sidebar-based plugin currently in private beta, is looking to offer clean and streamlined bookmarking and tagging. The plugin differentiates itself from the multitude of other tagging services by introducing a semantic dictionary of over two million tags. The basic idea: each tag will be defined, and that synonymous tags (say, New York City and Big Apple) will be linked together automatically. That should make finding your bookmarks easier later on.

After entering an appropriate tag for a page, the user is presented with a list of matching keywords, each of which has been defined in Zigtag’s database. For example, after entering “Apple” into the search field, I was able to choose from “the computer company”, “the pomaceous fruit”, and “the record company”, among others. The process is painless and the integrated dictionary is fairly comprehensive. If you happen to stumble across a term that isn’t defined, you can easily request to have it added to the dictionary (and can place your own temporary tag).

Besides the tagging functionality, Zigtag also offers a Digg-like thumbs up/down system, which influences a list of popular bookmarked sites on the Zigtag homepage. The site also has some basic social networking features, allowing for group-specific privacy settings and sharing with friends. There are a number of other handy features, including “Share Page” that lets you send snippets of images and text on a page to friends through email.

My experience with Zigtag was promising, but the plugin still needs some work. Using the sidebar can be pretty unintuitive, especially when you’re searching for something using multiple tags. And many of the synonyms I tried weren’t in the database yet (No mention of Bruce Springsteen for “The Boss”).

Zigtag’s biggest obstacle is the slew of other social bookmarking sites already available (Delicious, Diigo, and Twine, to name a few). The semantic tagging feature is fairly unique, but its appeal is still untested, especially against automated semantic taggers like Twine. Frankly, a lot of people are just going to stick with the simple but effective Delicious interface.

For those looking to try out Zigtag (Firefox only for now), you can grab one of 500 invites here.

Zigtag promises a lot – saying “Zigtag will transform how people search, save and share knowledge & information important to them” on the landing page that also asks for your email. I’m not completely sure what this means, but it sounds like it might be useful.

Consolidating your stuff to an online service is an exploding area right now – lots of the storage services are differentiating themselves by offering this type of thing. I’m looking forward to trying out zigtag when Reg is finally ready. Until then I have to settle for his flip card demo (seen in picture), and hope that some good software is on the way. Sign up to be notified of the launch here.

On a completely unrelated note, this is my first post from my new MacBook Pro. Wow, what a computer!