http://www.facebook.com/about/timeline/apps

Among 71 such apps, if installed with default settings: 58 apps would share your activities with the PUBLIC (81.7%) & 13 apps would share your activities with your FRIENDS (18.3%)

7 out of these 58 publicly sharing apps still don't warn the user BEFORE INSTALLATION about the public sharing part. You can only verify that individually after going to your own app settings page.

12 out of the 71 apps examined, explain (in 1 sentence) why they would like to publish activities, etc to the Timeline/Wall

19 out of the 71 apps examined, access data ANY TIME (i.e. even when not using that app) but ONLY 5 of them explain why they need such permissions.

10 of the featured Timeline Apps cannot be properly installed or need mobile app installation and hence were left out of this "study".

Raw data is available at: https://docs.google.com/spreadsheet/ccc?key=0AplwJ3hTKuqKdHlNajV2NlE5YXFucFRIdjFBV2VUQXc&hl=en_US#gid=0

Bottomline: I can't tell if Facebook is doing enough to make the privacy practices of these apps transparent to the users. I did this "study" after noticing many people being unaware about this "frictionless sharing" thing.