+1. I agree with everything he said. Typically in settings where you're meeting high profile executives, either people like yourself will want to talk to them for similar reasons as you or other executives may need to talk to them about business. This is the perfect time to say "I would like to continue this conversation, do you mind if we exchange contact info" (as Serg said). In my experience, I send an email taking the time to talk to me, highlight a few portions of our conversation and have been able to turn those conversations into successful mentoring relationships. Just be yourself, be poised and articulate and you'll profit. Good luck, bro.