What is a Webcomic?

At the most basic level, a webcomic is a comic which is posted on the web. Pure and simple. Is it a comic strip? Is it on the web? Then it's a webcomic.

While this definition is most general, it is not the most commonly used. Usually when a comic strip is described as a "webcomic," that means that it is posted either only or primarily on the web. Many webcomics in this sense do have print collections or, more rarely, comic book deals, but the vast majority of people who read their strip read it on the internet.

This means that while Penny Arcade [G] and Nukees [G] are webcomics, Dilbert, for example, is not, because it is primarily published in the newspaper.

How else are webcomics different than newspaper comics?