Gowalla has launched a new feature called "highlights" which it describes as "little rewards you can give to places that are important to your life". MG Siegler talks about the potential significance of such a feature. "Where this gets really interesting is when you bring the social graph into it," he writes. "So, for example, if I check-in near a spot where a friend of mine asked his wife to marry him, I'll get a message alerting me of that.