There is a feature very similar to this already but you have to login to use it. The fact that most of our users are anonymous is what makes a "like" button an idea with very marginal utility. Anonymous users can simply "like" their own posts and they can "like" them multiple times. I already see posters giving a "+1" to their own posts fairly regularly.

Hi jeff - people love hitting "like" or "heart" on stuff. I bet adding that functionality would be an nice upgrade to the site. what do you think?