Hmm...the only pop-ups I have seen are these 
survey ones that have just started happening 
about a week or so ago.  The window pops up, and 
it is like a 3 page long survey asking you what 
you think of ebay's services.  After ignoring it 
a few times, I went ahead and filled it out.  I 
haven't visited ebay since then, so I dont know 
if filling it out will make it stop. ;)

Nikki