If external website or applications have the ability to post to your timeline and thereby annoy you and your friends with spammy updates, there is a simple fix.
There is a page in FB that lets you delete any app which has access to your account – to post, your data, etc:
Delete any application you don’t want to have access to your account. You probably will, however, want to maintain the Facebook login for some of the applications listed there. It’s not a problem if you delete excessively as the next time you try to log into one of those services, it will ask you for permission again.
But better yet, just set the app to “stealth mode”:
For apps you do not want to delete, set app visibility to “Only Me”. Alternatively you can delete their ability to “Post on your behalf”.