You play it alot smarter then I did when the .mobi craze happened. I could have reg'd alot of great, very quick, high roi domains that were available. Instead, I thought of the future of the ext and reg'd names that will likely sell later. Maybe a year, 2 or 3. Meanwhile, names like collegeloans.mobi, gamble,laptops etc, are selling for thousands and thousands of dollars.
High overture, high bids, highly brandable names that sell and promote other peoples products, services etc are what you want.
Hope that helps a little bit,
HasRob..........