I have several accounts on eBay for buying and selling.
I've noticed that I'm restricted from bidding on auction style listings on every account now because I've 'reached my limit for bidding' and am directed instead to the buy it now price for that item.
Big Hmmmmm 
If you know the answer to this and are not just surmising, I'd be interested. I assumed it was due to a cople of unpaid items on one account, but that's well over 6 months ago.