I think it would be great if we all carried around "contact cards" for moments like that.

Kind of like a business card, right? Except without the formality. Maybe reading something like:

"Congratulations: You have been identified as a totally awesome person. We should keep in touch. Really.

1) This card can optionally be redeemed for one coffee or beer in the future. Bring friends; I'll buy for up to three people.

2) You can contact me using any of the information below. Whatever you prefer:

Facebook ID:

Email:

Number (for calling or texting):

3) To avoid potential confusion: No this card does not indicate romantic interest. We were just having an awesome conversation and that's a rare, cool thing in this world. Let's keep it going!"