So I've been wondering this for some time and it might be a stupid question but I really hope I can get a "sociable" teenager's response. Btw I'm 16.

When I'm on twitter/facebook I always see people posting or tweeting to their friends text me or DM me or message me. Why don't they just text them themselves?

One time I responded to this tweet from a kid in an older grade. I knew him from basketball. Anyway we had a little twitter conversation but then he asks me to DM him and I had no frkin clue what I was supposed to say. So my second question is: When someone asks you to msg/dm/text them what're you supposed to say in the msg/dm/text?