Subdomains and SEO

[mandy]

There has always been a long standing debate over whether or not to use a subdomain. Questions I commonly receive are... What is a subdomain? Is it hard for a sub-domain to rank well? When should a use a subdomain? What are the SEO benefits? What are the alternatives to a subdomain?...

What are the benefits to using a subdomain?

Let's say you had a site that had many categories in it. If you were to submit to directories you could submit each subdomain as it's own individual category and not get penalized. The links from the subdomains to the main domain would be looked upon as one way links from another domain...

full article: http://www.americanchronicle.com/article...cleID=8020

[jezebel]

What is a subdomain?

If you need to ask what it is, you don't need to use a subdomain.

[bargainbloodhound]

[quote author=jezebel link=topic=3392.msg12467#msg12467 date=1145139239]

What is a subdomain?

If you need to ask what it is, you don't need to use a subdomain.
[/quote]

That is true.  Smaller sites with low traffic really don't need them and should just focus on developing the content on their sites.  A lot of new site owners spend more time worrying about SEO (and all the terms that SEO marketers throw at them like keyword density, PR Rank, etc) than they do about developing the content on their sites and then wonder why they don't have any visitors/customers etc.

We use subdomains on some of our sites but SEO has nothing to do with why we use them.  There are 2 reasons we use them.

1. If we think that a section (feature) on one of our sites has the potential to grow enough to require a dedicated server(s) just for that feature, then we'll use a subdomain when we add the section so that it will be easier in the future to move that section of the site to its own server (and so there won't be any broken links or we won't have to write a million 301 redirects when it is eventually moved)

2.  (Server) Software compatibility- Some (many) of the scripts we use were originally written 6-8 years ago and PHP5 (and some other database software as well) isn't backwards compatible with a lot of older scripts, so sometimes we'll create a subdomain so we can continue running an older script but move the rest of the site to a more modern server.