Clearspring, the social-sharing company — in an effort to increase its business as a marketing analytics player — has acquired XGraph, a data science company.

Clearspring declined to provide the price it paid for XGraph, but said the deal was in cash and stock. The start-up raised $3.75 million just over a year ago.

The combined company has 85 employees — 70 at Clearspring and 15 at XGraph.

Execs at the the McLean, Va.-based company said the purchase will increase value to advertisers and publishers via audience targeting and data science. Clearspring is best known by consumers for its AddThis social-sharing tool, which provides a lot of detailed user data.

Clearspring raised $20 million in funding in May. At the time, the company said it planned to spend its new cash on acquisitions that leveraged data and built audiences more efficiently.

The New York-based XGraph focuses on modeling and monetizing the Web’s social graph.

“We get a lot of data points every day and making sense of them is something we have already been doing, but XGraph fits the bill to go even further in the multi-graph use of data,” said Clearspring CEO Ramsey McGrory. “It puts us in a position to be the market leader for the application of data.”

Key Compton, CEO and co-founder of the three-year-old XGraph, noted that the industry has become data-driven in new ways.

“People are connected to each other via social connections in a multi-graph platform,” said Compton. “I think there are some really interesting opportunities to access the data.”

Here’s the official press release for the deal:

Clearspring Acquires XGraph to Create Largest Multi-Graph on the Open Web

Company accelerates growth by deepening data team and technology

McLean, VA and New York. NY. — November 1, 2011 – Clearspring, provider of the largest social sharing and analytics platform, AddThis, announced today it has acquired XGraph, Inc., a leading data science company focused on modeling and monetizing the web-wide social graph. Clearspring’s massive reach and proprietary real-time data processing capability, coupled with XGraph’s audience technology, create the largest multi-graph platform on the web — mapping 1.2 billion user’s connections by brand affiliation, intent and social behavior.

The investment in XGraph’s data science capabilities marks another step on Clearspring’s rapid growth trajectory. XGraph’s team has deep data science expertise with applied backgrounds in advertising, sociology, mathematics and computer science. Their unique technology dynamically organizes users by shared connections and interests. XGraph’s team and platform will drive Clearspring’s existing efforts with publishers, advertisers and agencies forward while also setting the stage for new innovation.

“Clearspring is at the epicenter of two major shifts online — the web becoming social and personal, and advertising becoming data-driven and accountable. The common thread in both changes is data. To compete in this new world, companies will not only need the ability to access and process big data, but also have the ability to activate that data to create value for consumers, publishers and advertisers,” said Ramsey McGrory, Clearspring’s new Chief Executive. “The combined company has the people, technology and data to enable our clients to stay at the forefront of these changes. 2012 will be a breakout year for Clearspring.”

For advertisers, agencies and trading desks, Clearspring will immediately be able to provide the largest multi-graph audience targeting capabilities available on the open web. By using this technology to identify a brand’s core audiences and finding millions of other connected and like-minded people online, the company can now drive more efficient spending and increased campaign performance. Clearspring also plans to leverage this new capability to deliver publishers unique audience insights, monetization capabilities and actionable data products in the coming year.

“Most companies only capture one dimension of how we’re all connected, whether it be our friends or people we share with — a single graph approach. XGraph not only models these social connections, but also multiple other types of connections such as brand affiliations, intent and more — a multi-graph approach,” said Key Compton, XGraph’s CEO. “We’re truly excited to leverage our technology to unlock the value of Clearspring’s massive data set and help publishers and advertisers truly harness the power of the web-wide interest graph.”

XGraph is headquartered in New York with an office in Silicon Valley. All XGraph employees based in New York will join Clearspring’s office there. Clearspring plans to keep the office in Silicon Valley. The combined company will have 85 employees nationwide.

Though the measurement techniques for these kinds of syndicated Web tools are in flux, the McLean, Va.-based Clearspring has more than one billion monthly unique visitors, which it says beats competitors such as ShareThis and Meebo.

Clearspring co-founder and CEO Hooman Radfar said his company opened this year with its first profitable quarter, and that it will bring in tens of millions in revenue annually, “tripling this year and accelerating.” Radfar attested that he doesn’t need the new funding to operate, but rather plans to spend it on acquisitions.

What does he want to buy? Start-ups that “leverage data and build audiences more efficiently,” Radfar said. “We’re trying to look at companies that are younger and earlier than us but don’t have millions to build the real-time infrastructure we’ve built.”

Radfar said that beyond its current advertising business, Clearspring is poised to take advantage of all the data about users and content that passes through its system. “Data is the most valuable outcome of the social web,” he said.

Interestingly, Radfar observed that Chad Hurley and Steve Chen’s new company AVOS, which bought Delicious and a social media marketing company, sounds like it’s heading down a similar path of analyzing real-time audience data.

In a move to dramatically increase its traffic and give it more tools to offer publishers, Clearspring Technologies said it will acquire AddThis, the top bookmarking and content-sharing tool on the Web.

As with many social-networking start-ups, whether this disparate traffic can be easily translated into a reliable revenue-generating business remains to be seen.

The McLean, Va.-based Clearspring–one of several widget networks seeking to connect publishers and advertisers with social tools by helping them embed small pieces of content across the Web and monetize that content–would not disclose the price it paid for the Princeton, N.J.-based AddThis.

My guess: A few million dollars in cash and maybe more in some kind of stock swap.

What exactly is Clearspring getting for this?

For starters, a tiny icon with a lot of popularity to help it toward its goal of being the universal sharing standard in the new socially-networked Web paradigm.

Clearspring claims the pair together will reach 20 billion views per month and more than 200 million unique visitors, noting it would now have a “worldwide audience comparable to the seventh largest Web property.”

While adding up such piecemeal traffic is not quite the same to advertisers as a major central Web site like Yahoo (YHOO), for example, AddThis is the most used tool for sharing Web pages through email or from Web site to Web site.

Its main competitors are ShareThis and Yahoo’s Del.icio.us, even though it has only a handful of employees.

Of course, that viral success around universal sharing might not mean massive revenue generation, even if it is a popular consumer tool.

But Ted Leonsis, chairman of the board at Clearspring, and CEO Hooman Radfar said revenue would come via advertising and, eventually, valuable data analytics the services collect about Web behavior.

Currently, said Leonsis, AddThis has negligible revenue and Clearspring has about $10 million in annual sales. Neither is currently profitable.

Nonetheless, Radfar said, “AddThis is the biggest small thing on the Web,” referring to its tiny icon that expands to offer users a choice of Internet sharing services and updating tools to a variety of social networks.

And indeed, AddThis icons are widespread across the Web, seen mostly at the bottom of content items on big sites like Time.com and MySpace.

While some question whether a big business can be created through such a far-flung network, Leonsis–one of the early execs at AOL in its glory days–said it was how the Web is evolving.

“If you said to me 10 years ago that you were going to be successful by sending people away from your site, I would have said you were crazy,” said Leonsis. “But that is what the Web is about now, and having a central network that can track this is important for advertisers.”

Well, we’ll see about that, but Clearspring certainly has a lot of money to try.

The company has received more than $35 million in funding since it was founded in 2004. Investors include former AOL head Steve Case, as well as the venture firm New Enterprise Associates.

Clearspring has about 100 employees.