Question about buying expired domains
 

I see there are a number of sites that offer lists of expired domain names. This is probably kind of a stupid question. Is it bad for seo to buy expired domains? Could they be banned by google? I hate searching for domains and these lists seem to make it so much easier to find decent ones.

it is good for seo when you acquire a name that has lots of backlinks, such as finding traffic names with a PDDW.com platinum account

If you acquire a domain that was banned by google, just submit a reinclusion request and explain you are the new owner of the domain name. I've purchased thousands of expired domains and haven't had any issues with a banned name.

How can you tell if a domain is banned by google?

You won't have any listings in Google for the domain, and in Google Webmaster Tools it'll mention this to you. I forget the exact wording, but it should have a link to one of the Help pages that go over it in more detail.