Careless Twitterers are in for a healthy dose of Web 2.0 reality with the advent of a site that shows it's not really possible to purge errant tweets, as the microblogging site might have them believe.

It has long been plenty easy for world+dog to find a user's deleted posts by using Twitter's advanced search page. Now, a site called Tweleted offers an interface that makes it even simpler. Plug in the name of any Twitter user and it will display all recently deleted items.

It's the latest wakeup call to Web 2.0 aficionados that once they reveal personal information online, there's no taking it back - no matter what anyone tells you. British television star Jonathan Ross got an object lesson in the permanence of web postings on Monday when he Tweeted his personal email address, apparently by accident. He quickly deleted the post, but his email address remains available in public searches.

The same thing goes for the legions of Twitterers who got duped into revealing their "porn star name," which is said to consist of the name of one's first pet followed by the street name where one grew up (or the name of one's first teacher). As Sarah Palin and others can attest, the online availability of such information makes it much easier for scammers to glean details that facilitate password stealing and identity theft.

Plenty of Twitterers who played the game later realized their folly and deleted the posts. Of course, the ill-advised tweets are still available on Tweleted.

The discovery has prompted Graham Cluley, senior technology consultant at anti-virus provider Sophos, to call on Twitter to actually purge deleted tweets from its system. While that's not a bad idea, the move would have no bearing on search engine caches and, more importantly, any private firms that may monitor and cache material posted to Twitter, Facebook, and other Web 2.0 properties. ®