Although Facebook is testing a redesigned publisher that makes it easy to share public status updates, it’s important to remember that some comments left inside Facebook are always public – most notably, Wall posts or comments on Facebook Pages.
For example, when you leave a comment on a Facebook Page like that of New York Times’s Modern Love column, they are visible to anyone who visits – Facebook friend or not, Facebook user or not.
Similarly, Internet users who check out www.facebook.com/threadless and click on the Video box can see the comments left by Threadless’s Facebook fans.
For Facebook, making user-generated content on Facebook Pages public and searchable is desirable from an SEO perspective. But the important thing for users to remember is that it’s possible for people outside of your Facebook friends to see what Facebook Pages you’re a part of (via your public search listing) and to learn more about you through the comments you leave.