Currently Facebook Activitystreams feeds include entries for the Facebook user as well as their friends. This is a privacy problem in that it publically exposes posts from a person's friends, to people who may not be their friends.
Add an option to the feed processing to ignore such entries. Set the default to be true (ignore) for Facebook, false for all others. As new feed sources are discovered, this can selectively be turned on by calling the new Feed.setIgnoreStrangers() call.