swa66 - 11:01 pm on Apr 14, 2009 (gmt 0)

It tracks *all* your activity by intercepting all traffic at your ISP.

Something like adsense might be able to track you to some extend -should google care- to but only on those sites that actively participate in the adsense content network.

It adds/changes advertising on sites -> iow: at the expense of those making the site available to you.
- either the site will look like it's overloaded with ads
- either the legitimate ads are replaced
in any case:
- it violates the copyright of the original site IMHO
- it will reduce income for the original site owner

Anyway there are de-phormization scripts out there that tell users of affected ISPs to switch ISPs, and/or to opt the customer out by sending an opt-out cookie.