[Writing his name is a good start! He tries to offer an encouraging smile, even if he can't quite hide his surprise at just how unfamiliar with the technology Reim is.]

Ah, well, people use these things in a similar way to talking to others face to face. Only in this case, what you post is public. Some people use it to share news or information, others might just want conversation, maybe serious discussion. Some might want to share their interests with other people...

Why don't you start just by introducing yourself? Keep it simple.