GlimmerBlocker is a different kind of ad blocker. The problem with other ad blockers for Safari is that they are implemented as awful hacks: as an InputManager and/or ApplicationEnhancer. This compromises the stability of Safari and very often creates problems when Apple releases a new version. GlimmerBlocker is implemented as an HTTP proxy, so the stability of Safari isn't compromised because it doesn't use any hacks. It is even compatible with all other browsers.