Found this over at cribcandy...how cool!
You could probably keep it looking great if you didn't have kids. Otherwise I'm picturing a dusty, smoodgy mess...like this one from Cookie Magazine.
Washing it with soap and water, and maybe some mineral oil once in a while would probably keep up the luster a bit more.
My kids had a chalk board in their room. The real mess was all the chalk dust that fell on the carpet.