Here are the areas of mobile business I can come up with that can be very profitable (and are very profitable for the leading players), provided you get all your ducks in a row:
- Ad brokering (mobile Web or in-app)
- Deals / Coupons
- Gambling (betting, casinos)
- Payment (including micro)
- Digital goods (now mainly music, TV shows, movies etc)
- Bulk SMS
Games is kind of arguable in that very few are successful, but also very many think they are called. That’s not really the case with the other areas, where the initial effort is higher. Success stories are few for games, but media turns it into something anyone can be successful in, which is always the media’s stance during a gold rush.
The only way to easily (relatively speaking) become an operator is to use some other operator’s network, and simply charge a bit more towards your customers.
As you see, most of the business areas primarily involve small (per transaction) but very high-volume money transfers with not much actual product involved over time (at least nothing new produced per customer or per transaction) and with a predictable cut.
Considering how extremely successful banks are (at least in good times), handling pure money in and out of the company is the business model that generally works the best whatever you offer on paper, and is also fairly inexpensive to maintain and scale (including worldwide): Money is just digits from a technical stand-point, and digital products are just bits on a server that are re-used for each transaction.
Digital goods will grow very much over time, considering all things that you historically have bought on physical media will be downloaded or streamed. Also other types of digital goods can become very successful, like tickets, trading cards, custom avatars, resources in games (not the least cows and chickens), etc etc,
In the future we will not think content specifically for specifically mobile, tablet, PC etc. They will just be different gadgets for accessing different “views” of the same information.
Disclaimer: I don’t take responsibility if you fail based on the above advice. If it was safe and simple I would have done it all myself.