I just found this article on Facebook buttons, should I remove them from my site?
"Facebook Like-Buttons on External Web Sites - I can only warn you about the everywhere emerging Facebook Like-buttons on external (non-Facebook) web sites. When you are logged in to Facebook while browing the Internet. Due to the fact that the buttons are loaded through an embedded iframe (the non-Facebook web site embeds a Facebook web site), these buttons provide your personal browing habits to Facebook, even without you clicking on them."