Port 80 is the default port for the HTTP protocol.
So everytime you request an url in your browser without giving any port, your request will be send to this default port.
In the most cases, port 80 isn't blocked by firewalls which makes it very easy to use.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~free software according to purpose of usageXAMPP 1.8
for local development/testing onlyZend Server 6 (free)
for production environments
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~It's like porn for programmers