Well, I didn't hit "Senior" until this year. I have always enjoyed these forums, since the old one. I have "lurked" through almost all of the sections. Truth is, I intially signed up because I wanted to see all the options the new forum had as far as the user settings went. Basically I was selfish and wanted to control my surrounding when I lurked. Stupid reason, maybe, but it was justified to me. Also with being in the military, I was not always home to get involved in topics, but when I got back, I would start reading through what I missed.
When I became an instructor and found myself with a stable job, no more going away or 12 hour shifts through the weekend, I decided to get more involved in discussions. I still lurk more than I post, but to me that is what these forums are about. There are plenty of members who take up the slack!
Hope this gives you a little insight into the dark mind of a lurker