This looks great! I was just thinking I needed something like this a couple days ago, and then this popped up on HN today. I will definitely check it out.

I haven't had a chance to dig too deeply into it yet, but is the info stored in a session cookie and then you can decide if/when to write it to the db? For example, if I didn't want to write every unique visit to the db, but only when a user signs up, or signs in, or takes some action x, do I have the flexibility of when I write to the db?