Barry Schwartz wrote a piece on Search Engine Roundtable about Google penalties following to a new website.
So we know that if you have a penalty on your site and you move your site to a new domain and redirect the URLs to that new domain, the penalty will flow because of the redirects. That is known.
What I did not know is that if you took your site and moved it to a new domain but did not redirect the old domain to the new, that Google may also pass along the penalty without redirecting the URLs.
There was a Google webmaster hangout yesterday which delved into how Google handles these moves. If you have had a website run into problems with Google and were going to switch to another domain this segment is worth watching to understand how long it can take to get things right.