Thanks for the amazing article. I am very happy that the downsides of Zeitgeist are brought up since it pushes us developers to try to secure it as much as possible. Example: We are working on encrypting the whole DB using SQLcipher (https://bugs.launchpad.net/zeitgeist/+bug/787868). This bug was reported by someone very popular in the security industry and our mission is to turn Zeitgeist from spyware to myware. One of the usecases for Zeitgeist is sorting search results. If you have 30 results in the search mostly you want the results sorted via frequency of usage. This can only be done via tracking (more or less). So I hope we can push Zeitgeist to be more secure during the next 6 months.