We’ve written a lot about Pinterest lately as the image-sharing social network has been responsible for a near-meteoric rise in referral traffic for some sites.

But a Forrester blogger questions the true value of Pinterest to marketers.

“There’s no denying that Pinterest is fun, looks great, and a lot of people love playing with it. That is also true of kittens but no one’s rushing to include them in their 2012 marketing plans,” blogger Darika Ahrens says.

Why not? For one thing, she says, while Pinterest did grow by 4000 percent from July to December 2011, it’s still small potatoes. Google+, the “small” social network, has 400 million users. Pinterest receives 11 million visits a week, which is nothing to sneeze at but not enormous, either.

For another thing, that crazy study from last week is derived from Shareaholic’s proprietary data from its plugin and “is not necessarily representative of wider web user behavior.” (That isn’t to say it isn’t, and in fact it very likely may be—but the data isn’t there.)

“At most,” Ahrens says, “these early statistics put Pinterest as ‘one to watch’ for 2012, but should be way down the interactive marketers list of trends to consider for 2012 and firmly behind issues of multiscreen marketing, customization, local-mobile, effective media buying and attribution.”