Could you please describe in more detail what you exactly mean by subdomain and by "each short url in vazco_userurl"? Currently to my knowledge Elgg engine is not compatible with multiple subdomains although the vazco_userurl plugin should be fully compatible with multiple subdomains or domains.

With the vazco_userurl there could be a subdomain for each group and user page if set with the right .htaccess file, I just don't know how to do it.

Lets say you have a user name of  Administrator  

administrator.yourdomain.com

instead of

www.yourdomain.com/administrator

Search engines and certian advertisers prefer blogs to have their own domain, so the end goal is to have each blog to be able to have its own subdomain. I would think it should be simple to mod this plugin for this and would provide such more value to its use.

Perhaps something like the following:

RewriteCond %{HTTP_HOST} !^www\.example\.com [NC]
RewriteCond %{HTTP_HOST} ([^.]+)\.example\.com [NC]
RewriteRule ^(.*)$ http://www.example.com/%1 [L]

Souteast, I'm not sure it's possible, I would have to investigate this. We can code such feature as a custom development for you if you're interrested.