celgins - 11:46 pm on Oct 25, 2010 (gmt 0)
I would think that the "Like" button or "Recommend" button could be added to any page. You never know what a Facebooker wants to share with his/her friends.
If your site has articles, you may also want to consider using the "Comments" plugin. It will let users comment on any part of your website, but I think it works best with articles.