I am curious as to how web-applications are able to create sub-domains instantly for new users, for example,
example.blogspot.com. If I need to create a new subdomain for a website it usually requires that I log onto the DNS control panel and create a subdomain manually.
I have read examples about wildcard DNS and subdomains but that doesn't seem to answer the question about how a logged in user can create their own subdomain. I imagine that using the .htaccess file one could rewrite the URL to load a subfolder associated with a specific user.
The solution that I would consider would be to use a service like Amazon Route 53 and create new subdomains using the API. I'm not sure if this would be considered a good solution.
Additionally Tumblr allows you to point your domain name to their IP address or '
domains.tumblr.com'. Does this mean Tumblr have their own Domain Name Servers to handle these requests?