Opportunistic Mobile Social Networks (OMSNs) are kind of Delay Tolerant Networks (DTNs) that leverage characteristics of Mobile Ad Hoc Networks (MANETs) and Social Networks, particularly the social features, to boost performance of routing algorithms. Users in OMSNs communicate to share and disseminate data to meet needs for variety of applications. Such networks have attracted tremendous attention lately due to the data transmission requirement from emerging applications such as IoT and smart city initiatives. Devices carried by human is the carrier of message transmission, so the social features of human can be used to improve the ability of data transmission. In this paper, we conduct a comparative survey on routing algorithms in OMSNs. We first analyze routing algorithms based on three social features. Since node selfishness is not really considered previously in aforementioned routing algorithms, but has significant impact on network performance, we treat node selfishness as another social feature, classify and elaborate routing algorithms based on incentive mechanism. To assess the impact of social features on routing algorithms, we conducted simulation for six routing algorithms and analyzed the simulation result. Finally, we conclude the paper with challenges on design of routing in OMSNs and point out some future research directions.
