It works for me b/c the bulk of my "friends" on facebook are also devs, so they get it. Plus, while GitHub does have a newsfeed, it's always an overload of information.. I think this makes it easier to keep up with friends coding activity.
I assume my non-developer friends don't understand it, so they just ignore it.
The beauty of how Facebook bubbles up relevant information is what makes it work best. My mom may have seen it once, but probably won't see it much anymore.
I assume my non-developer friends don't understand it, so they just ignore it.