How soon do you reach out to people you've met at a networking event? (business, meeting)

[nj21]

I've been in Chicago for about a year now and just now started to go out to different events to start meeting people. This evening I attended a young professionals event and met quite a few interesting individuals whom I exchanged business cards with. When would be a good time to touch base with them and send an email or text message?

[BirdieBelle]

I would say within a week.