Digital advertising technology company OpenX has scored $20 million in its fourth round of financing, provided by the venture capital arms of strategic partners such as AOL and SAP, in addition to Asian investors Mitsui & Co and Presidio Ventures (Sumitomo).

Previous backers Accel Partners, DAG Ventures and Index Ventures also participated in the round, which brings OpenX’s total funding raised to $50 million.

The additional capital will be used to further the company’s growth, particularly in Asia (Japan and China to be more precise), where the online advertising market is still relatively nascent. In addition, the money will be used to accelerate the adoption of OpenX’s Enterprise solution.

OpenX CEO Tim Cadogen tells me the proceeds may also be used for strategic acquisitions of smaller firms in the near future – they’re basically interested in technology companies that can complememt them in areas where they foresee expansion (mobile ad exchanges, for one).

SAP Ventures led the investment and will take a board seat.

OpenX, provider of digital advertising technology for Web publishers around the world, has updated the ad technology platform currently in use by online juggernauts like Groupon, Orange-France Telecom and Excite Japan. The true strength of the platform is that it combines both powerful ad serving capabilities and real-time bidding on ad inventory within a single product (OpenX Enterprise, to be more precise).

The platform, which becomes available to all publishers today, is designed to help publishers efficiently manage a variety of digital revenue streams and optimize non-guaranteed and real-time bidded advertising demand. All in a single interface.

Another noteworthy component of the OpenX Enterprise platform is an integrated data collection and targeting system that allows publishers to use both proprietary and third-party data to enable audience-based media buying across their entire inventory.

The platform comes with a complete API framework and object-based design, making it relatively easy to integrate with other components of the publisher’s enterprise software stack.

Today, OpenX’ ad-serving products are used by more than 200,000 websites in more than 100 countries, and serve more than 350 billion ads monthly. Its other product, OpenX Market, is said to reach more than 400 million monthly unique users all over the globe.

Groupon has been using OpenX Enterprise for quite some time now to power ads on its website and email blasts in the US, but for French telecom giant Orange the adoption of the platform means a move away from Google’s DoubleClick. If anything, this shows OpenX can effectively compete with giants like Google, but also Yahoo and our parent company AOL.

The move is, however, not that surprising, considering both companies already had a partnership in place for the joint operation of a European advertising marketplace.

Los Angeles-based OpenX is backed by investors like Accel Partners, First Round Capital and Index Ventures, and is headed by CEO Tim Cadogan, a former senior Yahoo exec.

Under the agreement, Pasadena-based OpenX becomes a preferred partner to publishers for enterprise ad serving solutions and has agreed to promote Microsoft’s Content Ads monetization products and eventual future products to its own roster of web publisher customers.

OpenX said that publishers usings its recently launched OpenX Market and Ad Server products will be able to use MS’s Content Ads, and that the Redmond software giant will refer potential customers to OpenX.

Financial details of the advertising tech partnership, which has been in trial since August 2008, were not disclosed. Microsoft’s director of advertising business development Peter MacDonald did tell Reuters there will be the opportunity for both companies to make money in the deal.

OpenX, interestingly based on open-source ad-serving tech, claims it works with more than 150,000 independent sites that collectively serve more than 300 billion ad impressions a month. The company – formerly known as Openads – is led by former AOL CEO Jonathan Miller (Chairman) and ex-Yahoo exec Tim Cadogan (CEO). The company’s backed by over $30 million in funding, most recently having raised $10 million from a host of venture capital firms.

OpenX competes with companies like Google (which owns DoubleClick) and, notably, Microsoft because of its own aQuantive product.

More recently, we covered the launch of OpenX Market, an alternative online ad exchange platform operated by the Pasadena, CA-based company.

Today, OpenX is announcing that it has raised a Series C venture capital round to the tune of $10 million, which brings the total of funding raised by the company to a healthy $30+ million. Worth noting is that the extra financing is coming from a new lead investor, which is increasingly rare in these troubled times: DAG Ventures led the round, with existing investors Accel Partners, Index Ventures, Mangrove Capital and First Round Capital participating. Jonathan Miller, who recently was appointed as the new Chief Digital Officer of News Corp. also chipped in.

OpenX CEO Tim Cadogan in a brief interview didn’t want to go into detail about the valuation of the company after this round, other than that he was pleased with it. He did say that there was still large part of the Series B round ($15.5 million, closed in December 2007) left on the company’s back accounts and that there was no real need for them to raise money, “which of course is always the best time to raise money”.

Cadogan also told me the company is focused on making OpenX Market a success and to continuously add new publishers to its open ad technology platform Ad Server. To date, it has attracted over 38,000 publishers representing 150,000 websites for the latter, and Cadogan also informed me that Market has doubled since it launched a little over a month ago, with a current monthly run rate of over two billion impressions.

More strong figures: OpenX claims that from December 2008 to April 2009, the monthly run rate of impressions for the OpenX Hosted product grew more than 500% to 7.5 billion impressions, with the number of sign-ups for the new product now exceeding 10,000 in six months since its debut on the market.

(Disclosure: we use OpenX to power part of the ad serving here on the TechCrunch website)

OpenX, the largest neutral online ad server for website publishers, is finally ready to take the wraps off of OpenX Market, a service that has been in the pipeline for quite some time and was anticipated to make some waves in the digital advertising industry. I have my doubts about its disruptiveness, but website owners and publishers already using OpenX (we use it at TechCrunch) or planning to switch soon are sure going to want to take a closer look at the service, which is being launched in beta today.

In essence, OpenX Market is an independent marketplace where publishers can connect to advertisers directly to sell their ad inventory, while advertisers (either directly or via agencies) can access targeted inventory. Publishers define a minimum “floor” price for their ad impressions. OpenX Market then runs a real-time auction for each impression, with advertisers doing the bidding. If the winning bid from the auction is higher than the publisher-set minimum price, the higher paying ad is served and the publisher makes more money. If the winning bid is less, the publisher’s original ad runs.

It seems like a win-win for the publisher, since you have the ability to shoot for a higher paying ad without risking a total loss of money. If the higher bid doesn’t attract any advertisers, you are still able to fall back to your existing ad. The incentive for advertisers is that they have access to OpenX’s large pool of publisher inventory and ad space. OpenX’s has a publisher base of more than 150,000 websites that flows more than 300 billion impressions through the company’s software. OpenX publishers as well as non-OpenX publishers are invited to participate in the market. Advertisers can also set targeting parameters to find the best space that suits their needs, including user frequency, contextual categories, and technical/browser settings.

The company also rolled out a new version of its OpenX Ad Server 2.8 that integrates with OpenX Market. This lets publishers easily participate in the Market via an OpenX Market plugin, which allows publishers’ ad space inventory to flow directly into OpenX Market for advertisers to bid on.

An eBay-like marketplace for ads is not a revolutionary concept. Right Media and DoubleClick both have exchange marketplaces for advertisers and publishers, but neither are independent platforms like the OpenX Market, where any publisher, even those with other ad servers, can be a part of the bidding process.

OpenX (which used to be called Openads), has been growing rapidly under the leadership of former AOL CEO Jonathan Miller, who is the company’s chairman, and ex-Yahoo executive Tim Cadogan who is CEO. An open-source venture, OpenX has raised around $20.5 million in funding from Accel Partners, Index Ventures, First Round Capital, Mangrove Capital Partners and O’Reilly AlphaTech Ventures.

In August 2008, OpenX announced the launch of version 2.6, an update to its downloadable ad server and introduced a couple of features which spurred usage of the system, including a new API, dashboard and a speedier ad tagging system.

The ad serving solution is getting attention from around the world: its products are used in more than 100 countries and are translated into twenty-five languages by community contributors. The company says its community now counts over 35,000 total publishers that power more than 150,000 websites across the Internet.

OpenX, which is published under GPL, makes money by providing professional services to its publishers, something it started offering only two months ago. In addition, it sells premium support packages and enterprise-level Hosted accounts. A fourth revenue stream currently being tested is OpenX Market, a monetization platform that will essentially be something of an online market place where advertisers and publishers can partner up with each other.

OpenX raised around $20.5 million in funding from Accel Partners, Index Ventures, First Round Capital, Mangrove Capital Partners and O’Reilly AlphaTech Ventures. It was originally based in the UK, but has now moved its main headquarters to California with offices in London and Poland.

Last March, Google began inviting a select number of publishers within its AdSense network to test a new hosted advertisement management tool called Google Ad Manager. The search company has now announced that the tool is out of beta and available to all publishers with AdSense accounts.

Since its unveiling, Google Ad Manager has been seen as a direct threat to OpenX, an on-premise software solution (known previously as OpenAds and phpAdsNew) for managing the advertising campaigns on websites. Both solutions serve and track the performance of ad units sold either directly or introduced by third party networks like Federated Media or Google AdSense (which we use here at TechCrunch). But only Google can “use AdSense to fill unsold inventory or compete on price against other ad networks,” optimizing returns for publishers by serving up the most profitable ads from campaigns vying for the same space on a page.

As a hosted solution, Google Ad Manager also has the advantage of an easier setup and administration process since it doesn’t require any server-side installation or code maintenance. A hosted version of OpenX – which would necessarily depart from the company’s open source roots – has been anticipated for awhile now but has yet to be released.

Some will say the public release of Google Ad Manager spells serious trouble for OpenX. But seen in a different light, the release also enhances OpenX’s standing as acquisition bait for the likes of Microsoft, who wishes to compete more effectively against Google in the online advertising space.

Since its acquisition of DoubleClick, Google has also run the DoubleClick Revenue Center for publishers with large in-house ad sales teams.