Actually, the latest Twitter worm only appears to be an invite, and only appears so to Twitterers who aren't paying enough attention to their invites.
Which group may, unfortunately, include Tweeters among your employees.
Legitimate Twitter invites come in the form of e-mails containing a url; the link authorizes acceptance of the invitation.
According to Symantec, the new Twitter worm arrives as attachment, a .zip file in an e-mail that announces itself along the lines of:
From: [email protected] Subject: Your friend invited you to twitter!
The invite is supposedly in the attached .zip file; click it and you've invited a worm to pilfer your address file and to copy itself to removable drives.
This is far from the first Twitter worm, and it's likely to be far from the last. And the approach -- counting on users to eagerly respond to an invite without thinking about it -- is one tailor made for the type it/tweet it/go go go pace of Twitter.
Part of the appeal of social networks, of course, is the opportunity to connect with people, meet people, broaden our, well, networks.
But it's important that your employees understand what is and isn't a legitimate invitation, and know enough to tell the difference.