For anybody using off-site forums for their guilds, you might look to be sure you didn't have someone named zBarjinz (or similar - or just someone you don't recognize) as a recent addition. This person tried to access the Hellstorm and very old Eternal Reds forums, and did gain accesss to the ER forums before we noticed and banned him.
on the brotherhood guild forums there is an option to require account verification before you gain access to the boards. if you want to see what i mean go to hgbrotherhood.proboards.com. you will just get an error saying you must be logged in. I found this the easiest way to moderate who has access to the private information.