If you’re a Twitter user that actually uses the web interface, you might not want to see the new “Who to Follow” box on the right-hand side. This user script will get rid of it.
You’ll need Greasemonkey if you’re a Firefox user, and Chrome has user script support built right in. Go there, click Install, reload the Twitter page. All gone! If you want to uninstall it, you’ll need to head to the Tools -> Extensions panel and uninstall it in there.
Twitter – Hide Who to follow for Greasemonkey [userscripts.org]