by Elizabeth Kricfalusi, Tech for Luddites
Reader Mari wrote to say that some of the things she was posting on Facebook weren't appearing on her friends' home pages. She had checked her privacy settings and all her friends had permission to see them. She also knew they hadn't hidden her, so that wasn't the problem either.
There are actually two different aspects to Facebook's privacy settings. One is allowing or preventing someone from seeing a certain type of content.
I wrote about this earlier, in Privacy Controls in Facebook Pt. 1 and Pt. 2. As a reminder, you need to set these permissions individually for each and every application. So for example, if you wanted to restrict someone from seeing links to other websites that you post, you would go to Settings > Application Settings, then click Edit Settings beside Links.
When you restrict someone using these settings, they won't be able to see your posted links anywhere—on their home page, your Wall, your Boxes tab, or wherever else they might normally appear.
However, just because you give access to others to see the content, doesn't mean it will show up on their home pages. For that, you need to click on the Additional Permissions link and make sure that "Publish to streams" is checked.
If it isn't checked, your friends can still see your links if they go to your Wall or Boxes tab, but it won't show up in the News Feed (aka "stream") on their home pages.
Note: Some applications, like quizzes, ask you after you take them if you want to publish your results. In that case, they're also asking if you want it to post to your own Wall. If you say no, it won't appear anywhere on your profile.
Note 2: Even if you do everything mentioned above, Facebook also has a lot of bugs and they're very inconsistent (e.g. what works for me may not work for others, and vice versa). So the above instructions may not always work. If you do have other problems, don't hesitate to contact me, and I'll see if I can figure out the solution.