The July 5, 1993, issue of the New Yorker magazine ran a cartoon by Peter Steiner with two dogs at a computer. One says to the other, "On the Internet, nobody knows you're a dog." Today, with people interacting online in ecommerce, networking and even dating situations, that sentiment is becoming more relevant. How do you know the person you are buying from (or flirting with) is really who he says he is?

Online services to the rescue, of course. eBay has an ID Verify service, and BuySafe.com can even guarantee eBay transactions from their certified sellers. Yesterday, SquareTrade announced it is rolling out a program to verify the licenses of pharmacists and pharmacies selling drugs online. The Wall Street Journal reported that dating services are offering background checks. VerifiedPerson.com will certify the information people put in their own profiles, including height, weight and criminal history. (Let's hope they have access to your post-Atkins-diet records.)

Before you put your trust in these services and their approvals, make sure they are who they say they are, and that the authentication is valid. Just as fake escrow sites popped up to defraud online auction traders, it won't be surprising if some enterprising fraudsters set up fake services to steal your identity instead of authenticate it.

We may need a service to authenticate the authenticators.