Creating Subdomains Programmatically
Update your DNS settings of the particular domain so that *.domain.com all point to the same host.
Then, programmatically check and see if the first part of the URL used contains the subdomain you are looking for, and act accordingly. For example, if the first part contains a given profilename, then retrieve that particular profiles collection of data from your DB and display it to the user.
Make sure your web application uses relative links, so that if the user arrives at the site using a subdomain, that you don't redirect them elsewhere.
There is no generic way to create subdomains. You will need to call an API provided by your ISP or DNS provider -- typically SOAP or REST.
Either that, or use a wildcard domain (*).
On the IIS side, be sure to configure you application so that it doesn't use Host headers.
You could try:
AppDomain subDomain = AppDomain.CreateDomain("ProfileUserDomain");Although you may have to configure your DNS to allow request from your code. Dynamic DNS services could be your answer.