In the strictest sense you are talking apples and oranges. For example http://www.gothamglassworks.com/stuff is a subdirectory. It is part of your domain http://www.gothamglassworks.com. Whereas stuff.gothamglassworks.com would be a subdomain of http://www.gothamglassworks.com.

In the SEO world you want to look at subdomains as a separate entity from your domain whereas a subdirectory is part of your domain. Since anything in a subdirectory is part of a domain, you need to look at things holistically. Whereas you can look at a subdomain as a separate entity. That is why you sometimes see people putting their blog in a subdomain versus a subdirectory. They can then track each instance on its own. Plus there are all sorts of smart techie reasons for doing this.

IE Never host a secondary site in a sub-directory of your domain. Rather use a subdomain. This way everything is on its own – including your SEO efforts!

But seriously, I can understand how and why this is important! I think I am OK — but I had better watch my coding as my site grows!

Can you talk to us about how use of subdomains and/or subdirectories can influence SEO? )

Thanks again Helen — your are sailing above the SEO clouds!

Greg