Twitter Usernames VS Email Addresses

1) I have one of these "minimalist" business cards on my desk. From a recent tradeshow. It has a name and and email address (maybe a phone number, it's on my desk at work). I have no clue why I have it or what the relevance is. I looked up the domain name, it's a personal site I think (I was doing this last week). No idea if this guy wanted a job, was a consultant, had $1M of business waiting for me. I'm also not going to take the time to call or email and ask "who are you and why do I have your card again?"... IMO, unless you're a fucking spectacular dude, put some info on your damn card.

2) The difference between domain names (and thereby email and websites) is that you can own and control them. I'm not putting my Twitter ID on my personal card because I still have no guarantee that Twitter will still exist (or that I will still care about it, the novelty of Twitter is fading for me) in another year. I certainly don't see the value in directing someone to a 3rd party site out my control for them to contact me. And the process of someone finding me on Twitter, following me and/or "@"ing me, me seeing the message, having a meaningful conversation in 140 car burst, etc, just seems like a clusterfuck to me.