Interested in exploring how "new ideas and trends are spreading on Facebook," Facebook's Data Team, "mapped the top trending words and phrases in U.S. status updates for 2009."
Here's how they compiled the list of the top 15 status trends of 2009:
To generate the list, we started by looking at how many times each phrase with length from one-to-four words occurred in U.S. Facebook status updates, then we computed the rate at which each phrase occurred in 2009 compared to 2008. Using some data-mining methods detailed here, we analyzed important bursts in activity around words and series of words to find the key trends for the year. [...]
Because quite a few words and phrases were related to each other and correlated contextually, we grouped some of them together to form the final list that follows.
See the slideshow below to find out what were the top ten most-mentioned topics on Facebook.