Just Curious --- Please solve my ...dumbness

yeah well what jubba said is right.
now im running an HTTP server on my machine and anybody can access it through my IP address.
If you want to be able to make your own domain names, then (from what i know) you need to be running a DNS server, which matches the domain name with the IP address of your server. but if you wanna make your own domain releasing company and stuff i think you need to pay some fees to get ICANN approved and such… my information could be wrong, but thats what i got figured out =)