Until some time ago, I used Safari AdBlock to get rid of those annoying ads. But since Mac OS X Snow Leopard, Safari runs in 64 bits mode. Makes it a lot faster, and also more stable when a plugin crashes (Flash has that tendency sometimes). Safari AdBlock, however, only works when Safari is running in 32 bits mode. I’m not eager to make that sacrifice, so I went looking for something else.

That’s when I found GlimmerBlocker. It’s an open source ad blocker that’s implemented as a local proxy. I’ve been using it for about two weeks now, and it does it’s job quite well. Other than its expected behavior, one hardly notices it’s there.

Apart from ad blocking, GlimmerBlocker offers some bonus features, like throwing unrecognized URL’s (such as a search phrase) entered into the address bar at Google to perform a search, or keyword expansion (i.e. typing “gi something” in the address bar could initiate a Google Image search), that sort of stuff. It also allows pages to be altered arbitrarily, including JavaScript to traverse the DOM, before they’re sent to the browser, and it allows requests to be altered before they’re sent out to the server. It contains multiple filters by default, from not so aggressive to extremely aggressive (potentially breaking sites).

A drawback is that ads that slipped through the filters cannot be blocked directly from within the browser. Filters and rules are maintained from a System Preferences pane. A major advantage is that it works systemwide, for all applications, and even across the local network. When I have my iPhone connected to the local WiFi network, it too can and does use GlimmerBlocker running on my iMac.

After resorting to user CSS files for ad blocking temporarily (which doesn’t work very well), I’m happy that I now have a decent ad blocker again, one that doesn’t oppose any restrictions on the software or device using it. If it can connect through a proxy (I’ve never seen a networked device that can’t) it works.

Just some word-spreading, as the GlimmerBlocker web site asked me to do.

Update (January 12th, 2010)

I did find that GlimmerBlocker uses quite a large amount of memory for what is ultimately merely a proxy server. Consumes about 85 MiB here.