Question:  SUB DOMAIN

 

Is a Keyword rich SUB domain beneficial?

 

Keywords in a sub-domain are still a benefit, but if you do this, I would not include the same keywords in the main domain or the filename.  As time goes by I expect that keywords in domain names may become less important (in fact I think they already are).  After looking at my own domains, I think that keywords in a domain name (separated by dashes)  could trigger an over-optimization penalty.    I noticed several of domains that used keywords separated by dashes dropping from the top spot on Google for that term.  The site still ranked well for other terms so it was not a site penalty, just a penalty for that particular term.