To close out 2010, last week we ran a three-part series of simple lists -- the year's Top 10 Companies on Twitter, the Top 10 Non-Tech Companies on Twitter, and the Top 10 Movies and TV Shows on Twitter. All three installments were produced in collaboration with our editorial partner What the Trend, the trend-tracking company that monitors the rank and duration of every single topic that pops up on Twitter's global Trending Topics chart throughout the year.

Today I want to share a couple very telling pie charts produced by WTT that underscore a dramatic shift in the way that people used Twitter in 2010 vs. 2009. But first, some background: A few weeks back, responding to the ever-rising presence of so-called hashtag trends on Twitter (e.g., #WillGetYouSlapped, #IfSantaWasBlack, #iconfess, etc.), I wrote a column titled "Twitter Has Pretty Much Officially Become a Gaming Platform," in which I argued that Twitter was becoming a massive global playground for word-based games of wit. I noted that up-from-nowhere hashtag trends which inspire a global call-and-response are now, increasingly, crowding out real trends tied to breaking news.

In 2009, according to What the Trend's analysis, entertainment was the top category in Twitter's trending topics year-round, with 38% of the pie. In 2010, the top category was hashtag trends, with 40% of the pie -- up from just 9% in 2009. With that kind of growth in the hashtag phenomenon, other categories, like entertainment (28% in 2010), got squeezed.

In essence, Twitterers seem more and more interested in entertaining themselves and each other with hashtag musings than tweeting about commercially-produced entertainment.

P.S. Don't forget to check out What the Trend's newly expanded Year in Review page right here.

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Simon Dumenco is the "Media Guy" media columnist for Advertising Age. You can follow him on Twitter @simondumenco.