Yes i am hosting my server from my Comp

So when you own(paid for) a domain ex http://www.google.ca you have access to make a sub address like play.google.ca point to a number IP. Also known as DNS.

However since you are using No-IP, my theory is that it doesn't know how to point your minecraft server to a domain name.

You are hosting your server from your computer correct?

I have already Port Forwarded and everything All I want to know is how does PlanetMinecraft let some people use there IP as words Ex: CrimsonPvp.Zapto.Org

I tried using my IP that contains words and it did not work even though Me and other people connect through that IP.

No you need to follow this tutorial as well

http://www.minecraftforum.net/topic/554 ... -pictures/

All i do is enter that port and Im done???

Ok I am going to assume you are running your minecraft server from your computer, while running No-IP at the same time.

You still need to port forward Minecraft's port (25565) in order for others to connect.

So first, go to this site and enter in 25565 as the port number
http://www.canyouseeme.org/

If it says error, follow this tutorial on how to port forward.

http://www.minecraftforum.net/topic/554 ... -pictures/

Im new to this type of stuff so i have no clue what DNS is but I do use No-Ip...So In Simpler terms

You need to set your DNS records for crimsonpvp.zapto.org to point to the IP.

Just add another DNS record if your domain host supports it.