A similar rule exists in Japan, in which regulations governed by the Ministry of Internal Affairs and Communications (総務省 Sōmu-shō) limit the number of network-owned commercial television stations as a percentage of total national market reach. As such, commercial networks tend to have O&Os only in the four largest media markets (Kantō, Keihanshin, Chūkyō, and Fukuoka), and rely on affiliates to carry their programming in other prefectures. However, there are two major exceptions to the regulations. NHK is a government-owned, non-commercial television network and, since it is not covered by the ownership cap, owns and operates all of its stations. TV Tokyo Network is also not covered by the ownership cap due to the network's low number of affiliates (which are all owned by the network).
In 2009, after many years of decline, the era of secondary affiliations to multiple major networks (once common in communities where fewer stations existed than networks seeking carriage) finally came to an end at the smallest-market U.S. station, KXGN-TV in Glendive, Montana (which was affiliated with both CBS and NBC). The digital conversion allowed KXGN to carry CBS and NBC programming side-by-side on separate subchannels, essentially becoming a primary affiliate of both networks.
Affiliate marketing is commonly confused with referral marketing, as both forms of marketing use third parties to drive sales to the retailer. The two forms of marketing are differentiated, however, in how they drive sales, where affiliate marketing relies purely on financial motivations, while referral marketing relies more on trust and personal relationships.