• by Gavin O'Malley , Staff Writer @mp_gavin, February 14, 2012

Lured by the promise of better “interest graphs,” investors just ponied up about $6.6 million for social curation startup Pearltrees.

Great, but “what the heck is an interest graph?” asks VentureBeat. Apparently, it’s “more about what you know than who you know,” it gathers, along with “strong connections to purchase intent and other matters of concern to online marketers.”

“Put differently,” VB explains, “while social networks like Facebook focus on what you have in common with your friends … interest graph-based models [Pinterest, GetGlue, etc.] make social connections based on shared interests, not the other way around.”

According to GigaOm, the startup really needs the money to help scale its system for bookmarking and organizing, which is based around a clustered visual interface.

“Right now, Pearltrees is small and has moderate momentum, building up 350,000 users in the past three years,” GigOm writes. “Pinterest, by comparison, has achieved around registered 10 million in the same sort of time -- and one study suggests it is now one of the web’s biggest drivers of traffic.”

 “Some of [Pearltrees’s] most interesting technology … actually powers the discovery mechanism that is slowly becoming a more important part of the user experience,” notes SiliconFilter.com. “This so-called ‘TreeRank’ algorithm -- named after the way you organize your bookmarks/pearls on the site -- allows the company to interpret and expose the interest graph its users generate through their bookmarking  activity on the site.”

The technology follows the lead from Google’s PageRank and Facebook’s EdgeRank, according to TechCrunch. “In essence, it’s offering its own version of the ‘interest graph,’ a goal that many startups are chasing.”

To call the space crowded would be an understatement, GigaOm adds. “Whether it’s the new-look Delicious, Switzerland’s Paperli, shopping curation site Svpply, image service Mlkshk or another site, the fact is that almost everybody seems to want to help you save and sort and share the things you find on the web right now.”