Well, they didn't really need to try hard to hack in, as the BBC news reports they gained access to a 'small number of employees credentials' and off they went...
http://www.bbc.co.uk/news/technology-27503290
This is the trouble now a day's, systems still have the human weak links. They can use so many tricks to get employee usernames and passwords.
That's what all of the other media outlets are reporting as well..
However, this does also spread to the locale-based sites as well: ebay.ca, ebay.com.au, ebay.co.uk, ebay.co.nz, etc. So it isn't just the US that has the problem. You may be able your password by going to one of those other sites as well.
Also, the WSJ is reporting that ebay is putting together a page that asks and directs you to change your password upon login, and should be up shortly.
BL.