I have two questions:

First, doesn't using HTML5 mean that the site is accessible on fewer devices?

Second, how useful are check-in sites if you're an adult who is working full-time? I've always liked the idea of seeing where my friends are and maybe being able to meet up with them, but in general where they are is in the areas they live. Do I just need more friends, or to be going to a concentrated place like the villages or LES (NYC), or am I just totally failing to get what these services are for?