In the Comment section of your Dashboard, if I've commented on your site since 2.0 was launched, under my name in the comment will be a bunch of numbers and periods. Something like this: 209.33.221.23 (I made that number up)
With a site like this you just plug in those numbers (a simple copy and paste clicky clicky) and you have a bit of information. Mine, for instance, says I live in Rocky Mount, NC. Not entirely correct, but it's the right state. It also tells (correctly) who my internet provider is.
I'm really private. HOWEVER, the information provided does not really give anything away. It more or less semi-verifies what I've said about myself. That I'm in North Carolina. Yep, it's true. Hey Riis, you're really in southern CA somewhere. It's true.
But it doesn't give out with great accuracy our location, our names, stuff like that. It's my personal opinion that people who are crazy uncomfortable with that are people who are hiding something, who might be pretenders. Who might not be telling the truth about something and don't want us to know. If this prevents them from using the evil, invasive 2.0? Ok. We're protected from fakers.
Could someone use the info and with great skill, time, and investment find out more? Yes, I'm sure they could. But guess what? That could have always been done with the same skill and (psychotic) interest. There is, therefore, in my opinion, no more risk to the IP giveaway than there ever was in regard to personal privacy.
In fact? I think it's a protection. And beware. I probably IP stalked researched you.