I really think that platform limitation is hindering them more than they might think. Everyone I describe the product to says "Cool! Where can I get it on my phone?" and then is immediately disappointed when told what carriers it works on. Maybe I am just in an area (Boston) where no one uses these carriers, but it seems odd to ignore such a large segment of the population.

Also, they should really make their SDK freely available. I had a few interesting ideas for location-based services I wanted to toy with, but their submission page for their SDK was broken last time I tried to submit one of my ideas. I even went so far as to email the dev team with a plea for even a basic SDK to play with, but my request was soundly ignored. Why make it so difficult to develop apps if you want your platform to be used?

Just my .02.

They really need to integrate with AT&T/Verizon as soon as they can! Their service looks awesome, but... Exactly 0 of my 273 (thank you Facebook) college friends have Boost, Sprint or Nextel, and we're the kind of people who always want to know where everyone is "at" on the weekends.