Well, first I would say that while the question of the afterlife may be "the most important question of our time" to you, it is not that for everyone. The question of whether or not an afterlife exists, and what it is like if it does, is important to me as well, but we cannot assume it is of primary importance -- or even any importance -- for everyone.
Some people believe they already know what the afterlife is like, either because of their religion (as you mentioned) or because they have already done whatever searching they felt was appropriate and have landed on their own conception of an afterlife, one which works for them. Other people in bad situations (war, poverty, etc.) may be so involved in just trying to stay alive day-to-day that the question of an afterlife is not high on their list of priorities, or not on it at all. Others may have already come to the conclusion -- whether via study or just via their own feelings on the matter -- that there is no afterlife, and so for them there is nothing to pursue in that area.
I think another factor may be that no matter how much research one does, how many books one reads, how many discussions in which one takes part, ultimately there is no absolute proof of an afterlife (at least in my opinion -- I suppose this could be subjective) -- which is not to say that pondering the question and doing research are not worthwhile endeavors, but I'm guessing that some people feel it isn't worth the effort when in the end they cannot (or at least may not) come to a definitive conclusion anyway.
All of that said, I think there are still a lot of people who do ponder and research the question of the afterlife, a lot of people for whom it is an important matter. As far as this particular website, it used to be much more active years ago; I'm not sure why it has "died down", as it were....most likely there are a few reasons for that, but there's not much point in speculating. There are other websites about the afterlife and related issues which are still more active.
