Poisoning search results with content that leads unsuspecting users to spam or malware content is nothing new.  We've been seeing abuse of Google's PageRank system since early 2008 where spammers would artificially inflate the rankings of their spam web sites and send out email links which emulated the click of the "I'm Feeling Lucky" button on Google's search page to auto-redirect users through Google to fraudulent web sites. 

We are now seeing something similar with Twitter.  According to this post on Mashable's web site, spammers are using the accounts that they are setting up on the popular micro-blogging site to increase the ranking of certain topics so that they will appear in the list of Twitter's most popular topics and organically increase clickthroughs.  In some cases the sites that users are being directed to also can inject malware.

Be careful with these sites because as we have seen with some other Twitter exploits, the possibility exists that you could also have your account credentials stolen and used as another vehicle for distributing Twitter spam.  Twitter has been built to be easy for end users to use and interface with.  This methodology has been great to drive user adoption.  The unfortunate side effect that because of its popularity it has been an increasingly focused target for cyber criminals.