• by Laurie Sullivan  @lauriesullivan, December 5, 2012

Marketers are finding value in Pinterest. But while the social site doesn't provide analytics tools to prove return on investments, a startup called Pinfluencer does.

Trisha Mack Antonsen, Wayfair senior manager of social media, uses Pinfluencer to track engagement based on popularity of the content and determine how many clicks back to the Web site each pin drives.

A Wayfair contest on Pinterest hosted on the Pinfluencer Promotions platform shows a 255% increase in participants using the platform, with a 34% increase in eligible participants. The contest drove up Web referrals from the Pinterest page by 27%.

The platform allows Antonsen to collect and analyze the amount of new pins, re-pins, followers, best time of day for activity, conversions on the company's Web site, inbound links, revenue attributed to conversions, average order size, time spent on site and pages viewed. Prior to this, Antonsen only had numbers after participants emailed a link to their finished Pinterest board.

Wayfair is not the only brand seeing results from Pinterest. Pinfluencer Wednesday released a list of 50 brands, including Gilt, Martha Stewart, and Shape magazine, which have had success on the social site. The brands show follower acquisition rates of 156% percent and pins per day of 125%.

Earlier this month, comScore ranked Pinterest the fastest-growing social network this year, with the U.S. audience rising ten-fold to 27.2 million between July 2011 and July 2012. Most users connect on Pinterest through the PC, rather than mobile apps.

Data from a company called worldwidelearn.com, a resource for education and career information, estimates Pinterest's average visitor spends more than 90 minutes per month creating boards, categorizing, pinning and following other users' boards.