People are on Yedda as long or short as they like. Some people probably spend all day here, some people look around or ask a question and leave right away. All the answers are voluntary and nobody but the staff of Yedda gets paid. There's probably always a moderator somewhere checking on things, but they usually stay out of sight.
It's not like a chat room, if that's what you think. This stuff stays posted forever as an attempt to aggregate a huge amount of knowledge and experience. That's what yedda means in Hebrew - knowledge. The idea is that people come here to seek knowledge and to pass knowledge along to others. All of this knowledge is stored up and the staff of Yedda tries to make it accessible to searching.
They are probably to the point where you could pick subjects and collect all the posts into a book if you wanted to.