The flames were hot and nasty today as users swarmed to message boards to complain about AOL's "research" blunder, which exposed the search logs of more than 650,000 of its customers to the public.

"AOL, you betrayed your users," blogs Zoli Erdos, a Silicon Valley entrepreneur. "If they are any smart, they will boycott your services."

A blogger named TechCrunch put a finer point on AOL's gaffe: "The data includes personal names, addresses, social security numbers and everything else someone might type into a search box," TechCrunch notes. "The most serious problem is the fact that many people often search on their own name, or those of their friends and family, to see what information is available about them on the net. Combine these ego searches with porn queries and you have a serious embarrassment. Combine them with "buy ecstasy" and you have evidence of a crime. Combine it with an address, social security number, etc., and you have an identity theft waiting to happen. The possibilities are endless."

The hot comments are an outgrowth of AOL's revelation late yesterday that it had released a search log file containing some 19 million queries from 658,086 subscribers from March 1 to May 31. The online service provider replaced the identities of the searchers with numbers, but it failed to mask personal information contained in the queries themselves.

AOL apologized profusely for the mistake. "This was a screwup, and we're angry and upset about it," said AOL spokesman Andrew Weinstein.

But an apology may not be enough for some users. Paul Henry, vice president of strategic accounts for Secure Computing, said a forensic analysis of the log file turned up 223 Social Security numbers and some 70 credit card numbers, though only four of the latter turned out to be valid. "This should be treated as a personal data breach, not a mistake," he says.

"No shit, it is literally jaw-dropping how stupid AOL has been," says blogger Ben Metcalfe. "Don't forget this is the very data that Google refused to hand over the U.S. [Department of Justice] -- citing reasons of privacy."

The search log, which has been pulled down by AOL but remains available on numerous mirror sites, provides a classic example of the information that can be obtained by identity thieves by simple analysis of search engine keystrokes. Activity from financial, corporate, and pornographic sites can all be tracked back to a single user through a simple analysis of the log data.

Analysts also noted that the log provides a unique opportunity for users -- and hackers -- to analyze the way search engines are used. An evaluation of the log data could give phishers some insight on user behavior that would enable them to better model their scams, they say.

AOL, which currently ranks as the number four search engine on the Web, said the search log includes only queries from customers using the AOL client and does not include queries from non-subscribers who used its free search engine during the same time period.

— Tim Wilson, Site Editor, Dark Reading