UPD: IGN has now retracted their statement about the extended functionality of playing Black/White on the 3DS. I would assume they were thinking of the DSi vs DS w/ video chat. Thanks for pointing this out mark!
When you play Black or White on the 3DS you’ll get access to a yet unknown feature.
I made the mistake of not posting anything about this when I got a tip because I was like “who cares, we don’t know what it is”.