Mike,
I'm assuming you're seeing this in the "Subscribe" module, which is directly under the Login button. I don't actually see the text you're saying is there, but if I look at the HTML output on the page, I see the following Subscribe button inclusion:
fb:subscribe href="/community/" ..
The subscribe button is a way for user's to "Subscribe" to your own Facebook Wall Posts. You must specify a URL parameter in the Subscribe module that points to a Facebook profile. If not, the button won't work as there's nothing to 'subscribe' to.
Hope that helps explain, but if I'm looking at the wrong thing, or your still not sure, just let us know!
Thanks,
Alex