Social Network features

What are your baseline requirements for a mobile first social network? Mine is.. chat first. Past that, profiles and collaboration with groups. What are some of your ideas? Also, the closest I've seen to a perfect system is line Messenger ( which can be found here: https://play.google.com/store/apps/details?id=jp.naver.line.android ). The problem with line.. their interface SUCKS.. and that's ok, because it's just my opinion. Now let's hear yours!!