As an industry, we've already tried to solve the Business Card Problem. First were vCards, which were a good idea: a tiny data file with all your contact data you could (auto-)attach to an e-mail message. E-mail clients famously couldn't figure them out, and most v-card systems used the same default filename, but this solution at least has lasted. Hardly anyone uses them in the way they were intended (except on the Mac, sometimes, where the usability and app integration is pretty darned good), but at least it's still around. Which is more than one can say for most of the other bright ideas that have tried to solve the problem. Such as:

• In 1996, IBM famously demonstrated a future technology in which we'd exchange "business card data" by a "personal network" connected through your shoes. I haven't heard anything about it since then. Perhaps the fashionistas from Sex in the City could have made a difference in technology adoption should they have desired to do so; alas, that opportunity is probably gone.
• For a brief period, early Palm Pilot adopters practiced beaming their info to one another. This didn't make it because only geeks had Palm Pilots back then.
• Perhaps five years ago, my former colleague Bill Machrone wrote a wonderful column (lost in the mists of the Internet, I'm afraid, though I'm pretty sure it was for PC Magazine) suggesting that business cards adopt a standardized bar-code which could be scanned as quickly as a library card. I don't know why that idea didn't take off, but I wish it had.
• Two years ago, the camera in a Motorola phone, available in China and Hong Kong, doubled as a business card scanner. But it's not exactly standard equipment in the smartphones you and I are using today.

Notice one thing: we aren't using any of those technologies. Most of them, I think present too high wall for the non-techie user (such as the salespeople who work trade show booths) to adopt.

But this is still a problem that is itching to be solved. Certainly, I am waiting for a better solution that can be easily accepted (even by people as techno-phobic as my sister).