Coming Soon to Facebook: A ‘Dislike’ Button
bits.blogs.nytimes.com
bits.blogs.nytimes.com
If I do nothing, that's less interaction on Facebook. If there's a third option — "dislike" — then I (and many others) will use it and provide more interaction on Facebook. I think +1 or "hug" is a better fit but regardless, it means a net-increase in interactions.
More interaction by users is better for them. Surprised this didn't happen ages ago.