Honestly, it doesnt make a whole lot of sense. When registering a domain name to build or for resale, one of my primary checks is what would I develop it into? The first issue is what would you use BlackMale.com for? now .mobi?
My recommendations are to stick with primary TLD's and specifically stick with .com - although .mobi is selling, I still dont see as much development in the tld to start investing heavily. I think next year you will see some prime names dropping in this extension when the hype wears off.
Also, I might recommend tracking down older or expiring domain names and buying those as opposed to fresh registrations or even obscure TLDs. There is definetly a market and good value to be found.
Good luck,
Justin