News.me and Instapaper - Sync your articles to your phone as you leave your house, so that when you're underground on the train, you have all your content right there
Now - Combs instagram for clustered activity in your area, and then notifies you of what's going on (i.e. movie in the park that people are enjoying)
Dark Sky - Alerts you when it is going to rain in your precise location, based on radar
Square - Automatically logs you in as soon as you arrive at the coffee shop or wherever
What it boils down to is location is automating various parts of user interface. Making your life better in the process. (this post a tldr version of http://adage.com/article/special-report-digital-conference-s...)