Two approaches. Built your own, or partner. REI took the partner approach, and it seems to be paying off in terms of number of downloads.

The base logic for apps is good. The main challenge being to attain first-mover advantage. It comes back to RUE. Relevance, Utility, and Entertainment. What's your app going to provide?

Great overview of the latest wave of technologies to come out. These are more and more key parts of marketing programs as well as product development. Marketing firms make their best margins in things their clients can't come close to executing on. This layout of tech platforms is a good road map to better margins.

When the facebook beacon disaster hit I thought to myself, why didn't Blockbuster just create it's own app with easy opt in if they wanted? why spend all that money on a "new" facebook intiative when all the tools are there. The only reason was to force it on users, and look it blew up in everyone's face. Gamefly is doing this the right way, looking it as brand awareness, and starting soft and easy so consumers build trust. With really cool social networking features to come later.

Looks like Facebook is all about fun. That can be good for brand marketers, but for those trying to drive near-term sales, it could be different. The recent reports of very low interaction rates with Facebook ads supports that.