What's mean a subdomain on Stak website?

Simple, if you have a website or you desire to have it...
...if you like stak's website...
...you can request a subdomain here... for example:

Your name is Paul and do you like to have a webpage for you named paul...
...here you can put your webpage and you can have an url like that: paul.stak.altervista.org

...and you webpage will be linked in the list of subdomain!

I want a subdomain here!