Amano

I'd like some advice on networking. I'm at a conference that will go on for a couple more days, and last night I chatted and exchanged cards with a potentially very good contact. I plan on following up with an email, but my question is when to do so? I've been told the general rule for networking is to follow up 24-48 hours after a meeting or conversation, but when does the clock start ticking when I'm at a conference that goes on for several days.

It seems silly to email him near the end of the conference or before the end of the conference, because in theory I could still go up to him and have another conversation with him. I also don't know if he even has an internet connection at his hotel. At the same time, I don't want to appear like a slacker or for him to forget me if I wait 24-48 hours after the end of the conference (which will be 4-5 days after our conversation).

Any ideas from people more savvy at networking than I am?

Thanks in advance!