On my gaming site we have these channel pages which is basically a unique page that has content very specifically tied into the topic. Like for instance our E3 2010 channel had a liveblog for the event, and a list of games and known information about them.
If the string is in the URL, it shouldn’t matter too much whether it’s the subdomain or a subdirectory. Google have said that it doesn’t matter which you choose, both will work equally well in search rankings.
What you should do is re-write one URL onto the other (using a 301 redirect) so that users end up on the same page, whichever URL they hit. This will ensure that search engines recognise the different URLs are different routes to the same page, and will treat it as a single page. Not sure where keywords fit into that?
Isn’t it funny after 10 years of Internet the people still can’t be trusted to not put the www. infront of a sub domain?
The Internet is 10 years old? Try 52 years old!
Even the World Wide Web is 19 years old…
And as usage grows, there are more and more less web-savvy people using it, people whose first reaction to getting a URL is to type it into the Google search box. Most sites don’t use subdomains. There are a lot of people that don’t believe you can have a web address of any sort without the www…
I can’t see any reason not to allow both routes into the site. I would certainly make sure the first one works - if you rely on only the second one, you will get people typing in www.e32010.domain.com, which almost certainly won’t work. It also means that when people type the URL in a text format (eg email, blog comments, forums, social networking), it would automagically linkify it even if they don’t include the http://, which won’t happen if it doesn’t start with www. On the other hand, the second format is shorter, which makes it preferable for linking within restrictive contexts, like Twitter, where every character counts.
In terms of SEO, it will make near enough no difference - as far as the search engines are concerned, a URL is a URL, and as long as the internal and external navigation is consistent about which one to prefer, the actual structure of the URL won’t make any difference.