WebWasher 3.2 Beta 3 is among the most powerful and thorough ad blockers. It uses multiple techniques to determine whether static images should be blocked, checking ad dimensions as well as both internal and user-defined lists. It also tries to block pop-up ads, some or all actions taken by scripts, and Web bugs.
If an unwelcome ad gets through, right-click on it and WebWasher adds the URL to your block list; you can also usually edit the pattern to include ads from the same site. In testing, WebWasher's filtering-by-size feature occasionally blocked pictures that weren't ads. Also, the script-blocking feature sometimes caused pages to display improperly. But generally, WebWasher is excellent at stopping unwanted scripts while leaving useful ones running.
WebWasher's useful privacy features include a Referrer filter (which hides the identity of the page that referred you), a Prefix filter (which blocks URLs that have built-in tracking), and an innovative cookie-control mechanism that converts persistent cookies into ones that last just long enough for, say, an online shopping session, then vanish.
Like FilterGate, which is not as good at ad blocking, WebWasher doesn't require browser setting changes. It can't block ads or cookies that are served via encrypted links (URLs beginning with https://). So far, the company hasn't officially designated WebWasher as a final release, and unfortunately, WebWasher doesn't work with AOL's browser and isn't guaranteed to work with Windows XP. Nonetheless, the product is well worth a look.