I've just discovered this and I'm horrified. Facebook posts to the news feed of all my friends not only the things I deliberately share but also EVERYTHING I comment on in the various pages. I comment a lot in pages under pictures, jokes, and so on without telling it to share. Sometimes I'll write 20 comments in pages and not share anything, but Facebook posts it ALL. I didn't realise until I watched a friend of mine log on to their own Facebook account. My friends are getting overwhelmed by these posts.

How do I stop Facebook doing this? I want people to see my shares and my status updates, nothing else.