According to the Facebook Blog:
Since first launching the “Like” feature in 2009 and the ability to comment on News Feed storiesin 2008, we’ve seen these features become central to the way people communicate on Facebook. They’re two of the most heavily used features on the site and have proven to be a simple way to discuss posts and show appreciation for the content friends share on Facebook.
Facebook coins one of my favorite phrases, calling it a peanut butter and jelly idea. I’d have to agree.
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