http://www.w3.org/Mobile/posdep/HPw3cwapref.html
Developers interested in creating location based services had to wait until carriers allowed the requisite devices and started offering reasonable data plans. It was only in the second half of 2008 that Apple's app store launched. As a Palm developer around 2002 I talked with fellow enthusiasts about leaving digital "graffiti" at various locations using GPS, for only friends or subsets thereof. I looked into developing for Verizon with J2ME and BREW, but there was no clear path to getting an app published, no public API to get location, and data plans were out of reach for most of the public.
Apple managed to pry its way in with the 2007 release of iPhone, allowing users to see what is possible when carriers relax their restrictions. Other competitors are still effectively locked out though, due to device "subsidies". Your monthly bill on AT&T remains the same whether you buy a $200-$300 subsidized smart phone or spend $300 more for an unsubsidized model not sold by the carrier. Most people don't seem to understand this and simply see unsubsidized phones as a rip off. There is a big penalty for choosing a phone outside the carrier's selections, and in the case of Verizon, outside choices aren't possible. This leaves little incentive for new players to enter the smart phone market, because after all the R&D, you are likely to be locked out.
It was only by around 2007 that there were indications that the carriers may offer a path to developing a location based services, with check ins and tracking friends being one of the most basic applications. Just about the time this patent was filed for. By that point though, a lot of location based service ideas had been floated around by enthusiasts for a couple years already.