Back in late 2006 I was working in South Africa and was in the mall one day when I received a bluetooth marketing message over the phone. This was completely amazing and something that I'd never seen before in the UK or anywhere else. Anyway I blogged about it here and got in contact with the company behind it, WCIT.
Anyway, the founder of the company behind that initiative has written a fantastic analysis of his experience starting, and ultimately closing that business.
If you're interested in learning the lessons of an early player in mobile location based marketing this is an essential read. It's also interesting to anyone interested in startups. You can download the pdf for free below
or you can grab the book for Kindle here