Any time you make a web page, compose a song, write a poem or draw an image
you automatically get copyright to your work, that's the international law.
Basically what it means is nobody can do nothing with your creation. "All
rights reserved" Unless you say so.
A license is the tool for giving people permission to do something with your
work. You can choose any license you want to.
In the free software movement we're interested in software that's made
available under a free software license. Similarly the free culture movement
is about audio, video and images released under free licenses. The two
movements use somewhat different licenses as a song is somewhat different
from a computer program.