The most important things we can do are to continue to post great MOCs here, and to comment on each other's posts. If all the action happens on flickr, no one will have any reason to come here. It will be an uphill battle, but it's doable. I've heard before that classic castle continues to coexist with flickr, so there's no reason that we can't do the same. It will take time, though.
Publicity is good. Don't spam other forums, but don't be shy about putting a link in your signature. If you have a blog or Web site, or even just a Facebook page, put up a link.