Broadcasting something to an undefined group of people doesn't really count as social interaction in my book. Even if it did, I'd consider it a pretty lazy and meaningless method thereof.

Your characterization of online social interaction is plain wrong. You can't assume everyone else approaches Twitter or Facebook the same way you might. People learn from each other online, argue with each other, start relationships, start/run businesses, share photos and videos, etc. I have no idea how you can overlook all the positive things to promote such a negative view.