Comment 2 for bug 1088333

I see the exact same URL when clicking on the "Log in to use your Facebook account with <Ubuntu>." Ubuntu hyperlink from within the signon-ui / online accounts page.

It directs to a page containing a large bandaged thumbs-up image and the wording:

Sorry, this page isn't available
The link you followed may be broken, or the page may have been removed.

While I would ordinarily trust a service built into Ubuntu, this would imply to me that I shouldn't - Facebook doesn't recognise Ubuntu as an official app.

Ubuntu 13.04, utilising the Chat only element of the Facebook connector.