1. The Ticker isn't actually revealing any new information. But it is showing users a lot of information they probably wouldn't have bothered to look for in the past. They can see any activity from friends that they let you see. If a friend is commenting on another friend's wall (even one that you're not connected to) and that wall is set to be publicly viewable, you'll see that post in your Ticker.
2. Every post you make on a public fan page will show up in all of your friends' Tickers. Fan pages are public, so this information will be accessible to anyone.
3. Check a post's security level before commenting. There is a small icon under each item in your news feed. Hover over that to see who can see the post. The globe icon means the update is public and anyone can see it. There's also an icon for updates that only friends can see. You can also set a custom list of people.
4. Be extra mindful when commenting on a public post. Any comment you leave on a status update will be sent to the Tickers of every person on your friend list. All posts from fan pages are public.
5. Your own activity won't show up in your real-time Ticker. This can make it hard to troubleshoot exactly which parts of your activity are being published. Facebook must be assuming that you already know what activity you're doing and don't need to see it.
6. Facebook says Timeline will be available in a few weeks, but you can enable it now.
7. Once you've enabled Timeline, you'll have some time to clean it up if you'd like. Even those of us who have always been very careful about what we post on Facebook will be surprised by some content on our Timeline. Any post on the Timeline can be hidden from view, deleted from Facebook or changed to be viewable to just some of your friends. Once you've cleaned it up, you can then choose to publish your Timeline so that it's viewable to other Facebook users.
8. With its new class of apps, Facebook is looking for "frictionless" experiences. This means that you'll see fewer dialog boxes asking if you'd like to publish a certain kind of activity to your newsfeed. When you first set up an app, like Spotify, it will ask for your permission to access your information and let you set that behavior to public or friends-only. You can also define a more specific list of friends to have access to that information. But then you won't be asked again. It will become much easier to forget which apps are broadcasting your activity. After you give Spotify permission, each song you listen to will be broadcast to Facebook.
9. Subscribers are people who sign up to receive your public posts in their news feed. If you've enabled this, anyone who adds you as a friend will automatically become a subscriber. If you confirm the friend request, the person will be elevated to "friend." If you turn down the friend request by clicking "Not now," that person will still remain subscribed to your public posts.
10. When you defriend someone, they will still be subscribed to your public posts. If you want to defriend someone and prevent them from seeing what you post, you'll have to also block them.