You know, it's not my intention to insult or criticize anyone (which I inadvertently did, off the board, on this topic a few weeks ago) but what draws new surfers and potential members to a media website initially is news - particularly if the place is a reliable source of leaks or breaking news.
Some people remember the bump-up in TrekBBS participation when "Star Trek Series V" was announced, and expect that to happen again. But the main event that drew so many new people here then was that Christian obtained and published the first detailed inside info about the premise and the characters of the new series - "Enterprise." TrekWeb got on the map because of earlier reporting about "Star Trek: First Contact" (and some of their staff was publicly sore about TrekBBS scooping them on "Enterprise").
That was then. Boards like Trekweb and TrekBBS are old news now, literally - they both function mainly as bundlers of stories that appear first on other sites. It's the sites that are getting early and inside info on the movie that are already growing and will continue to grow.
Now, if TrekToday gets hold of the first full-on effects shots of Abrams' Enterprise or costume photos of Pine on the bridge or a detailed synopsis of the script and publishes those before everyone else then that changes the ball game again.