In the era of Twitter, the rolodex card can be mercifully small. My card for BJ Fogg only has one additional piece of information, his Twitter handle (@bjfogg), and from there I can reconstruct enough contact details to get a message through to him in a few different ways.
I know him through an acquiantance with Jerry Michalski, and in my mental rolodex his card spins to the top when "persuasive technology" comes to mind. If I sort the rolodex geographically, his card goes in the big pile of people I know in the San Francisco Bay area. The sort by cafe puts him at Coupa Cafe in Palo Alto, since that's a good spot near Stanford; we've never met there, but if I had to suggest a place, that would be my first suggestion.
Here's an index to only a few of the things I've written that have referenced or quoted BJ Fogg.
August 2004: Seven steps to innovation.
November 2005: Positive feedback loops and numerical indicators of progress.
December 2011: Grand resolutions vs tiny habits.