Not really an accessibility issue for users, rather for webmasters.

If you have a massive user base, each with their own page, what are the pros and cons of giving them a subdomain versus giving them a path? I'm mainly looking at it from the webmaster's point of view, but does it effect the users as well? Is one more manageable or flexible than the other?

MySpace uses paths, e.g. http://myspace.com/myprofile
Bebo uses subdomains, e.g. http://myprofile.bebo.com

Many other sites use one of these methods, blogging sites inparticular.

I don't have any experience of websites this big but I would still be interested to hear your thoughts guys.

Thanks