Great info! Thanks for posting it. I've been thinking of the business card route for a while now. It isn't that expensive, and it's an excellent way to get local people on your site and hopefully make new IRL friends.
my site is a Anime/Manga based site, so I join the same type of sites that allow you to advertise your site on theirs(i do stay around and post). Second I put my site's logo in my sig. I also get to know people and ask them if they'll join. Third I require my staff to bump threads every week, the more people talking about it the more people think about joining.
I have a blog at www.canthoville.com which has PageRank 4, so I saw many peoples come and comment on my article to get backlink to them. Always I accept polite commenting. So I think they make their sites advertised for free.