I was indeed trying to make a distinction between a library and a full application or web site. From an entrepreneurial perspective I think it's important to focus on products rather than libraries. It's far easier to monetize a twitter client than it is a twitter library.

If you want to get a programming job it's a good idea to publish a lot of stuff to github. Personally I find it more satisfying to build applications vs. libraries. Others find the opposite to be true.