Here are two items in the comics business that illustrate some fundamental issues regarding creating and selling properties.
Mike Strang pitched a comics series called Weird Adventures in Unemployment and sold it as a "work for hire" project to Platinum Studios, a comics packager. The idea languished for years until it was finally drawn up. The editor he did business with left the company and the editor's replacement decided not to publish the property in hard copy, only to publish on the web. He further decided that the idea needed to be changed. Mike Strang is unhappy about how he was treated and has gone public with his complaints.
While I'm sympathetic to what happened to Strang, he didn't do much to understand the deal he was offered or to protect his interests. Selling an idea is no different than selling a car. Maybe the new owner will allow you to drive it or take your advice when he wants to soup it up, but the new owner has every right to paint the car a disgusting colour or to junk it. He owns it; you don't. To think otherwise, regardless of what's been said to you, is delusional.
Neil Gaiman, who's a best-selling author, pitched an idea called Interworld that he created with Michael Reaves to DreamWorks and other places. Nobody wanted it. Eventually, the two of them wrote it up as a novel, got Harper Childrens to publish it and now DreamWorks is interested in making it. Gaiman certainly has enough clout that if he's going to sell an idea as "work for hire" he's going to get a better deal than Michael Strang. However, due to luck, Gaiman and Reaves now own the copyright to the published story, so any negotiations from this point forward will favour the two authors far more than if the work had been sold purely as a pitch.
The animation business is very different than publishing. If you sell a TV series or a feature idea, you lose ownership of it; you've sold the car. If you're savvy, you got a good chunk of cash and negotiated specific benefits for yourself. However, if you don't have a track record in the marketplace, you don't have a lot of leverage to negotiate those things.
Today, with the web, you can bring your ideas to the public. In a sense, you're publishing your own work. Besides establishing ownership, you're also bringing an audience of some size to negotiations with any larger corporate entities. You might, like JibJab, opt to keep ownership of your properties and just license the rights or you might opt to sell outright. In either case, you're negotiating from a stronger position than pitching initially to a company.
Mike Strang's experiences should be a warning to everybody. Unfortunately, he won't be the last one to make this mistake.