In this paper, we analyze and compare general development and individual behavior on two non-profit internet-based hospitality exchange services -- bewelcome.org and warmshowers.org. We measure the effort needed to achieve a real-life interaction, whereby the advantages of mutual altruism arise. The effort needed is the communication quantified in units of time. Since the amount of effort is not obvious to individual users, the development of the effort investing strategy is investigated. The impact of individual behavior on general development is discussed.