Lack of trust in Facebook may hold back ad sales Associated Press Copyright 2012 Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed. Updated 02:22 p.m., Tuesday, May 15, 2012 Few users surveyed in an Associated Press-CNBC poll say they click on the site's ads or buy the virtual goods that make money for it. More than 40 percent of American adults log in to the site — to share news, personal observations, photos and more — at least once a week. [...] the company is getting better at making money from its user base, but it has a long way to go to fill out the market capitalization of nearly $100 billion implied in its IPO pricing. Google, another online advertising company that walks a similar line between ad targeting and privacy, makes more than $30 per user, per year. "Somehow Facebook still hasn't stumbled upon a model that's proven consistently successful for marketers, or that brings in the massive revenues to match the site's massive user base," Forrester Research analyst Nate Elliott said in a blog post. The rest came from the purchase of Facebook "credits" for the purchase of virtual goods, like cows in "Farmville" or chips in "Zynga Poker." If Facebook wants to help stores selling something other than virtual bling, it has to overcome skepticism among users first: