Download and double click the extension file to install it into Safari 5. It allows you to block:
- Google Adsense
- Google Analytics
- Google API (may break some sites)
- Facebook content
- Embedded YouTube videos
[crarko adds: I tested this, and as far as I can tell it works as described. It may be an interesting exercise to run Little Snitch before and after enabling Incognito and see what actually is being blocked.]

