Another malicious worm hit Twitter over the weekend, days after the micro-blogging site reached near-meltdown from a technically similar attack.

This time around the danger came from clicking links contained in micro-blogging messages beginning "WTF [URL]". Last week's more serious onMouseOver problem struck when users moved their mouse cursor over an infected tweet. These messages contained hidden JavaScript code that exploited a cross-site scripting problem - in the case of the WTF worm a CSRF (cross-site request forgery) technique is in play.