Facebook is constantly playing catch-up with the other social media sites, yet it still remains most people's go-to site.
Twitter has had hashtags seemingly forever. Google+ gets hashtags from day 1. Months (maybe years) after G+, Facebook finally implements hashtags.
Twitter is also the first to do trending topics. G+ implements trending topics from day 1. At some point, Facebook gets trending topics (I never noticed them until recently.)
G+ auto uploads photos into a private folder. Dropbox, which isn't even a social media site, auto uploads photos to a private folder. Facebook follows suit.
I hope the next feature that Facebook steals is the editing of photos and an option to auto enhance photos. Even if they do though, I'm sure it will be extremely lacking compared to what G+ does.