Should Facebook have a unlike button?

[john]

French developer Thomas Moquet took matters into his own hands by creating a cute (albeit useless) Firefox extension that adds a dislike button to Facebook, letting users who have it installed mark things they don't like.

In order to make the tool work, Moquet had to use his own servers, which keep track of every item that's disliked as well as who clicked it. Any other Facebook users who have the extension installed can then see who disliked it right next to the usual like list.