Whenever privacy options are present, it is always interesting to know how they get used. Whenever we tweak the design or experiment with default settings on Flickr, we see subtle behavioral shifts. I was just looking at the statistics for groups and was surprised to learn the following:

• 72% v 28%: public v private groups
• 47% v 53%: postings in public groups v postings in private groups
• 2:9 ratio of postings per active public group to postings per active private group

To illustrate that defaults matter, in our original design where users had to explicitly make photos public (and couldn’t switch them back), the percentage of public photos in the system hovered around 45%. In the new system where you can set a default for photo privacy settings and the default ‘default’ is public (and you can change the setting at any time) just over 85% of the photos are public.