In the late 1980s, there were ten full members: the Soviet Union, six East European countries, and three extra-regional members. Geography, therefore, no longer united Comecon members. Wide variations in economic size and level of economic development also tended to generate divergent interests among the member countries. All these factors combined to give rise to significant differences in the member states' expectations about the benefits to be derived from membership in Comecon. Unity was provided instead by political and ideological factors. All Comecon members were "united by a commonality of fundamental class interests and the ideology of Marxism-Leninism" and had common approaches to economic ownership (state versus private) and management (plan versus market). In 1949 the ruling communist parties of the founding states were also linked internationally through the Cominform, from which Yugoslavia had been expelled the previous year. Although the Cominform was disbanded in 1956, interparty links continued to be strong among Comecon members, and all participated in periodic international conferences of communist parties. Comecon provided a mechanism through which its leading member, the Soviet Union, sought to foster economic links with and among its closest political and military allies. The East European members of Comecon were also militarily allied with the Soviet Union in the Warsaw Pact.