The other trick I use to help with filtering is the +label trick where my email will be name+label@gmail.com and the filter is set to catch the +label part. I didn’t think of it previously but you could apply the same trick here with something like name+social@gmail.com. That way, instead of setting a filter with all your different social sites you could have one argument on the filter and every site you use name+social will be grabbed. The only problem will be if you want some messages from a social site to come to the inbox (DM from twitter for example but not “follow” notifications).