The new version of our search engine optimization tool has the functionality. It is implemented on DPUG but the links are "Like | Share" but I am unsure it is a good fit for APUG. The benefits of it are that when content is "liked" you can then go to various views to see all of the most liked content on the site. In a list of threads if you see "75 likes" next to the thread title you know it must be good. Some might find that useful. Individuals also end up with counts of how many likes they have received, maybe this encourages better posts not sure. The share option allows for instant sharing of APUG content to social networks. This is what it looks like on DPUG (it is somewhat non-invasive):
There are also "like trees" that show most liked content throughout the site. I have not shown any screens of that.
But, like some say, myself included... I am getting a bit burned out on the whole social networking thing. If people really want this we could probably have it available as an option that you activate, but not on by default.