I'm working on idea #2 along with other location aware services for mobile browsers. The domain I've picked up so far is http://this.st (standing for This Street); figured it'd be easy to type on a phone. One of the services is going to cater to schools, starting with mine (University of Waterloo). MIT has done a great job with m.mit.edu and it will be a good benchmark.

Other services for densly located areas will be in places like malls and theatres.