With online shopping hitting the $211 billion mark according to Forrester, more and more shopping-comparison sites have sprung up, raising questions about their independence from particular sellers, according to E-Commerce News.

Though it's hard to tell whether a comparison-shopping site is completely independent, there are signs to confirm its legitimacy - aside from having instant brand recognition, like CNET and BizRate.

Lesser-known comparison sites display customer confidence logos such as those supplied by TRUSTe, VeriSign, and BBB Online. Consumer shopping portals also provide confidence logos, such as BizRate's Circle of Excellence, CNET's Certified Store, Price Grabber's star ratings and Shopping.com's Trusted Store.

In the end, though, the long-time traditional players can usually be counted on to be trustworthy. Sites like CNET, Consumer Reports, Shopping.com, Pricegrabber and Shopzilla offer a history of reliability and independence from preferred retailers.