I find myself lurking a lot but very rarely posting, which is mainly because I rarely have much to add to a thread; most of the time, someone else have already expressed my thoughts on the matter. It's also a matter of time, as I sometimes start writing a post but end up not posting since I don't have the time to finish it; I often do forum reading while drinking my morning coffee, and generally that means I have time to read but not post. So I often end up only posting about things which are important to me, or of special interest.
As for what happens, for me specifically, I started HRT slightly less than a year after joining here, and went full-time/started RLE a few months later, when I was certain that the psychological effects were beyond doubt beneficial (to say it mildly... "HRT saved my life" is more accurate). I plan on having SRS sometime around summer 2016, but have not made the final decision yet. I have been accepted by almost everyone close to me, and things are going well - almost scaringly well. My response to HRT is beyond what I expected physiologically as well as psychologically, I have had virtually no problems with things like changing my name, people at my university have been wonderfully accepting, as are the people I train martial arts with. If there are any naysayers, they have mostly kept their mouths shut. There are of course still challenges, but they are minor.
This also contributes to me posting less; I don't really have much to post about, as in I don't have many questions or issues that arise. If annoyed with something (or someone), I tend to vent to my friends rather than online (and I am fully aware that I am privileged to have friends I can vent to!). I do sometimes search the site for older threads to answer more specific (generally HRT or surgery related) questions, and I mostly find what I need. Other times, I do browse the forum to see if I can answer something in other posters' threads, but as I mentioned, most of the time someone else has already said what I wanted to say. So it more or less boils down to me not needing to post a lot, combined with feeling I have little to contribute to other threads.