If it's not already being served up to mobile devices today, it most likely will not be tomorrow.
99% of .mobi names useless for any real world application. Unless you are going to spend the money to develop, advertise and maintain your .mobi domains, I feel you probably wasted much of your money.
Think about it - if mortgages, car loans, diet tips etc etc were wanted by mobile users, existing websites and companies would be serving that information using existing websites and technology. But they are not, and there is a big reason why - there is ZERO demand.
Ringtones, video, wallpapers, stock quotes, sports scores, traffic reports etc - these are being served up this way already via .com's, .net's. cctld's etc, so why would the owner of these sites spend money on .mobi, then spend the money to develop a whole new domain? Some of these .mobi will probably do okay if their new names don't infringe on existing .com owners TM's.
Every other .mobi - sorry not going to happen.
I'm with the naysayers.