One of the most common tasks of an executive producer is being the primary source of money to fund the project. This person can either directly invest his/her own money or locate investors who provide funding without being credited. Other people may provide enough direct funding to be credited as producers, but the executive producer usually provides more money than anyone else.
An executive producer often oversees the entire production in multiple capacities. One of the biggest tasks is watching over all the money and making sure the production stays within budget. This can involve handling personnel decisions, especially with the director and crew, and looking over/approving scripts that are written before production. An executive producer may even write and/or direct episodes or editions of a certain show.
The show's original creator is often the most prominent executive producer, especially when it comes to television. This person is more involved than anyone else on the production staff, because the creator usually helps provide money originally to finance the project. The creator is usually the first executive producer listed in the show's end credits.
The executive producer is responsible for finding a distributor for the show once it has completed production. The distributor is the company or person who buys the production and finds an outlet for it, it theaters for a movie, or on a network for a television show. The executive producer must therefore be a salesman for the show, convincing a studio or other distribution company that the show is worth purchasing, and then spending the time to sell it to a network.
Some executive producers may be little more than figureheads. These are big-name TV/movie producers who have built up fame and recognition on previous works, but lend little more than their names to a project to help provide funding and publicity for the project.