For a long time there been a major security flaw with following links from Twitter. When a link is shortened via a service like cli.gs, bit.ly or tinyurl the user has no idea of where they will be directed upon clicking. The best way to manage this so far has basically been to click on shortened links only from users that you know or trust. That’s the danger of clicking on a shortened URL from Twitter Search or trending topics - you may end up clicking on a link to a site with malware or other issues that you would rather not encounter.