I understand that jomsocial enables the next vanity web addresses to exist

domain.com/profile/jack

although this is not strictly a vanity url the men at jomsocial say it might be too intensive for performance to achieve this.

ok well could an imaginative regular expression convert a minimum of

domain.com/jack to domain.com/profile/jack ? to ensure that it really works for every profile that could get produced, therefore it needs to be clever and employ variable 'username', within this situation 'jack'

How can other frameworks address the routing for here it is modrewrite ? could it be php etc....

thank you for any ideas or perhaps the solution.

You need to have the ability to get it done with htaccess with something similar to this (untested)

RewriteRule ^/(.*)$ http://www.domain.com/profile/$1 [L]