Welcome to the Q&A Forum

Thanks for clearing that up Rand, I'll stick to the one subdomain.

These links are the one's that got me thinking.

http://www.mattcutts.com/blog/subdomains-and-subdirectories/

http://www.webmasterworld.com/google/4339166.htm

Also, I was under the impression that sub forums on one domain were viewed as different sites in the SERPs but try searching for 'bodybuilding'.  You'll see www.bodybuilding.com at the top and a list of pages from that site and 2 further subdirectories are included (forum.bodybuilding.com and bodyspace.bodybuilding.com).

Although a personal preference only, I prefer subdomains and think forum.domain.com and blog.domain.com look much better than domain.com/forum and I would do it this way IF the rankings were unaffected.

I've had a good read on this one and just wondered whether the info on the below link is still valid 3 years on:

http://www.seomoz.org/blog/understanding-root-domains-subdomains-vs-subfolders-microsites

My main site is a forum but I want to add further content in the form of a blog.  It seems logical to me that domain.com/blog/ would make more sense than blog.domain.com as the the content and inbound links to the blog would also help the forum where it's on the same subdomain, however I just wanted to make sure that was still the case as I've also read that Google now see a subdomain and subfolder in the same way if set up correctly in webmaster tools and this solution would look neater if that was the case.

Thanks all.

Thanks for all of the replies, much appreciated.  I think I shall leave it as it is as there doesn't appear to be any merit to moving across to the www. apart from the very small loss of link juice when people link to the www. and it gets 301'd.

Is there any benefit whatsoever to having the www. in the URL?

My domain is quite long therefore I've not been using the www. however a few people have mentioned it's good practice to include it.

The www. forwards to the main URL (non www.) and I've set my preferred domain name in webmaster tools to the non www.  so I'm thinking that should all be ok.

Just hoping I could get  some of the experts views to make sure this is all ok.  The site is a year old and I'm just starting to really get going on the link building so it's not too late to change if I'm wrong.

If others link to my site and include the www. will the link juice be passed, as I suspect many will include it without any thought?