Are Justin Bieber and Ashton Kutcher no longer Twitterverse kings?

justin-bieber-ashtonkutcher-twitter.jpg Twitter apocalypse now? Stop the presses, quit messaging on your iPhone and step out of the Hootsuite: Justin Bieber is no longer a permanent trending topic and Ashton Kutcher is about to be trumped on Twitter by a pop princess!

Bieber -- love 'em or hate 'em -- has practically owned Twitter's trending topics list. That was until this week when the social media site announced it had tweaked its algorithm on how it's calculating trending topics.