How does this work?

I'm curious to some of the inner-workings of this product.

Here's why:

When I check the IP address of my blackberry, it is a RIM assigned IP. Which makes sense. I would have thought it would be an IP registered to my carrier, but anyways...

When tethered to my Mac, the IP shows up as being registered to a company called Abacus America in San Diego. Why is this? Is Abacus the parent company of Tetherberry? If so, is all my web-traffic when tethered tunneled through to Abacus? Is it going through a proxy of some kind? Are they caching my browsing habits?

Interesting...