Something is not created from nothing. There must be some seed planted to foster growth of an creation. One may not realize they are creating something partially from the ideas, inventions, or any other part of another persons work but that is what happens. With the picture below (borrowed form clips above) creativity or invention is shown to have 3 main types of formation. There is copy, which is taking one idea and claiming it as your own. Transforming is taking an idea and changing it anywhere from a slight paraphrase to a complete reconstruction. And finally combine, which takes two or more ideas and takes parts of each to create a 'new' idea.
There are several laws that have to do with copyrights and patents and owning ideas/inventions in general. This makes creativity seem almost as a bad thing, especially in the way I've described it thus far. But creativity and other's role in it is anything but a bad thing (in most cases). Songs have been sung, movies have been made, phones have been...phoned. Invention is somehow at once communal and individual. We bring our individual thoughts together with others to make something new.
This is a TedTalk explaining what I said in a much cooler and funnier way (mostly the Steve Jobs quote) that took part in this blog post creation - http://youtu.be/zd-dqUuvLk4