When a thread/post/whatever gets caught in the spam phrase filters, it will also show a list of links that have been placed (as they can be hidden easily within e.g. commas or periods)
Useful spam phrases:
It is trivial to bypass XenForo email bans using sub-addressing (also known as "plus addressing") or, for some email providers such as Gmail, by inserting . dots between the local-part characters of the address.
Attempt to register a new account with...
I have (in the past) volunteered as a "moderator" on a small Xen-Foro forum and one of the most time consuming tasks involved preventing copyright violations from being posted. It can be a real hassle especially when all a member has to do is open another window in their browser /// [CTRL-C]...