"This means we can do things like fight spam more effectively, detect system and reliability problems more quickly, and build better features for everyone by understanding how Instagram is used," Instagram wrote today on its blog.
One key change, however: Instagram's new policy specifically authorizes the sharing of user data with "Affiliates," which it describes as "businesses that are legally part of the same group of companies that Instagram is part of, or that become part of that group" -- i.e., Facebook and its family of businesses.
Such affiliates, Instagram says, can offer their "own services (including providing you with better and more relevant experiences)." This mostly likely means one main thing: Advertising! Instagram also separately notes that it "may" (translation: will almost certainly) share user data with third-party advertisers.
Facebook announced earlier this year that it would acquire Instagram for $1 billion, and closed the deal in September. At that time, Instagram announced that over 5 billion photos had been shared across its network.