Facebook is testing out a Want button
In the SDK code Waddington found an XFBML tag <fb:wants> which would equate to a “want” action, or a want button. The button is not publicly listed but Facebook has confirmed that they are “always testing new Platform features.”
Since the Want code would function similarly to the Like button, users could “want” things across the web and feed that data into their Newsfeeds and Timelines. This could be a huge deal for product sellers on the web, which could further push users to their sites. However, to many the Like and Want button may end up being so similar that there will be no difference, and the extra button may end up being useless.
Don’t you think it would be nice to have a dislike button instead? I know the web has been asking for it since the Like button was introduced (it will probably never happen, but I want it). To see exactly how Facebook is able to take your Likes and turn it into contextual data, you may want to read this write up.