[livestream]

How can I check if a site uses a database or the parameter inside the url are used for other things ?

['Snorlax]

You could do that by hoping your target has an SQL injection vulnerability.
Other than that, use common sense. Does it have users? They're most likely stored in a database.

[Phizo]

What content is available on the website? It should be fairly obvious to determine by simply that.
If there is little content and you're still curious, consider performing a port scan to determine whether or not the service is active.