instagram can have this one for free
In light of recent Facebook purchase of Instagram, please consider adding the following "feature":
Assignable filters for photos that include friends that can be the default filter used on a photo of that friend by another friend in their social circle.
Person A takes a picture that includes Person B (who is later determined to be within Person A's friends list)
Person B has a preference of filter to be used by any friend who takes a picture that includes Person B.
These filters could be merged as more persons are noted in the same picture who happen to have a filter preference.
Preferences could be based on the various social circle hierarchies/organization:
family/friends/stranger/g+ style circles in the future.
Person A will have the authority to reject the application of a filter (which could include blurring Person B out entirely).
Cheers and you can have this one for free,