Unity Lens API in Ubuntu 11.10 have been improved greatly with better filters and data sources. Both Ask Ubuntu and Reddit Lenses have been updated to match with the new API and now they are better equipped.
To add the PPA and install these lenses, run the commands below:
sudo add-apt-repository ppa:markjtully/ppa
sudo apt-get update
sudo apt-get install unity-askubuntu-lens unity-reddit-lens
There is also a Web History Lens in PPA, but it is not working for me. If you want to give it a try, run the command: sudo apt-get install unity-web-history-lens