A television advertisement is a span of television programming produced and paid for by an organisation that conveys a message. Advertisement revenue provides a significant portion of the funding for most privately owned television networks. The vast majority of television advertisements today consist of brief advertising spots, ranging in length from a few seconds to several minutes (as well as program-length infomercials). Advertisements of this sort have been used to sell every product imaginable over the years, from household products to goods and services, to political campaigns. The effect of television advertisements upon the viewing public has been so successful and so pervasive that it is considered impossible for a politician to wage a successful election campaign, in the United States, without use of television advertising. In certain countries, France for instance, political advertisement is forbidden on television.