Bollocks. If someone gives you a businesscard with their phone number on it it is an open invitation to call at a later date. That's what it's for, it's not a collectible.

Otherwise keep two sets of cards, one with your phone number on it and one set that has just email or IM information on it.

It is really bordering on the arrogant to assume that someone is reading your blogposts in order to figure out what they can or can not do with the contact information that you gave them.

If you think you are too important to be bothered by 'mere mortals' you might as well stop handing out business cards.

And god forbid someone actually wants to talk to you. Just imagine, where do these people get the guts to do that.