there’s also a company philosophy that realtime location sharing is the future. They believe that startups like Foursquare, which requires manual updating, represent out-of-date technology.
While I'll agree that check-ins are a little messy, they represent an important difference that goes unmentioned- I check in when I want people to know where I am. At all other times, my location is unknown.
That's important to me. I don't want everyone knowing where I am on demand- not that I'm doing anything shady, but it just weirds me out and I don't see the benefit in it. Glympse and my own project, Taxonomy (http://www.taxono.my) do selective sharing- I manually choose who I want to share with, and when. For me, that's much better. But maybe I'm not representative of most people?