You would see mostly;
1) Thought Provoking MessagesSome would tell you something, something very serious and thought provoking, in their way.
2) Life's mission statementsSome would express their mission statements i.e. what they want to achieve or want to become in long term.. I just realized these mission statements are much impressive than what I wrote in my business studies' assignments.
3) Loud MessagesSome would be trying to communicate a loud social issue. Their words can be hilarious or cliche but you won't deny that statement.
4) Routine Life ComplainsSome would be expressing their emotions and misery of life. This is the category where they turn themselves into poets. Apart from sad statements, expect some truly hilarious statements too. Expressing life situation in such short statements is an art you cant master, its a natural gift, isn't it?
5) Mind BogglingSome would be so mind boggling that you can generalize them. They can be sad, hilarious, funny, anything.
There can also be usual sad poetry and common cliche statements as well like "yeh sab meri maa ki dua hai" kind of.