Sadie from the UK reported that a number of ebay groups are having issues, defacements, deletions etc. 

I've been unable to confirm this, however if any of our UK readers have any additional information please contact us
(specific links, screen shots etc).

Update 1
It looks like there is an issue at Liveworld/ebay with the groups.  There are now a number of groups which you would typically not find on an ebay site.  From the posts on the site Liveworld is looking at it.  In the mean time you may wish to steer clear of the site.
One of the more likely avenues is keyloggers on user accounts to grab the userid and password, but this has not yet been confirmed.

Mark Hofman
ISC Handler On Duty
shearwater.com.au