I was just curious to this quesiton. Let's say you had a site and then bought a couple of urls and forward them to the site, but a lot of seo to all of the urls. Would this help you with SEO, or would you most likely get the urls banned from google?
Yup. Google will see it as duplicate content and won't rank it very well. So very bad for SEO. Unless you do permanent 301 redirects from all those URLs. In which case you could have keyword rich urls which would be good, but I'm sure googlebot won't like to siff through too many 310 redirects.
I would've thought it'd be diluted content rather than duplicate. http://www.sitea.com forwards to space on server http://www.siteb.com forwards to same space on server It is only really useful if your brand is quite easy to mispell (I have registered "Anglesey" and "Anglesea" domain names), I think that any pagerank/seo will be split between the two sites.