Let me make this short and clear – Twitter has acquired Summize!
The Summize website www.Summize.com is now redirected to www.search.twitter.com
Now if you visit either of the above URL’s that i posted you will see the Twitter Search Page up there is a Hot Trend Lister which tells whats the hottest topic/trend at the moment.
If you want to resemble this with something then that something could be the Google Trends!