This article has made me think. Flavour of the month at 3GSM were handsets with built-in GPS capabilities. A million and one startups are trumpeting mobile search, mobile navigation and a whole bunch of other ideas, based on the assumption that increasing numbers of phones will have mapping capabilities. Nokia, Google and others have been pushing their mapping strengths.
All this seems to be based on the success of in-car satnav. But there's a problem... all the maps & navigation software is very vehicle oriented. It's of much less use to pedestrians - either because certain routes are inaccessible (lack of crossings, railings etc), or because many rights-of-way (footbridges, paths through parks, alleyways) aren't on the system at all.
So for example, if I wanted to get from my house to a restaurant in Camden Town in London, my GPS-phone probably wouldn't suggest a nice (and much quicker) walk through Regents Park. Interestingly, though, Transport for London's journey planner does get it right.