Business Cards and Hacker Groups

I'm very happy to announce that this year I'll be attending my first software development conference, RailsConf 2009, thanks to the generous sponsorship of my employers, the Australian Medical Council. This fantastic opportunity has brought forward some thought on what I had already planned for this year: to make some business cards.

I like the idea of having my key contact details ready on a single card to hand to someone new if we've started a conversation that we'd like to continue later. I can see the utility particularly in situations where I meet people in a business context or in opportunities for discussing freelance work. It means we can talk as much as possible about whatever we like without needing to worry about the clumsy manual transmission of contact information.

I'm not so sure about the value of business cards in the context of this conference and a big group of hackers. I am keenly looking forward to the chance to meet many new people at RailsConf, but I do not know how to most easily preserve contact with them. For example, when I meet people at RORO events, I typically ask them if they are on the twitter, then get out my iPhone and jot their name down into the notes app. I can foresee this becoming difficult to scale to larger groups.

I'd like to ask your advice. Would it be useful to have my twitter/web contacts down on a card for giving away in these same situations in the future? Is this acceptable in this community? Or should I just take things as they come: not worry about remembering the details of everyone I meet, accept that they will take much the same approach, and throw away the idea of business cards for these situations? How do you use business cards?