Subjective norm as a main social factor has been found to affect users' willingness to switch to an alternative (Bansal et al., 2005, Ye et al., 2011). Since most users regard MIMs as means of maintaining relationships with their friends, they will perceive an alternative MIM as more attractive and have a stronger switching intention on account of the recommendations of these people (Hou, 2015). Thus we consider subjective norm as a pull factor that motivates MIM users to switch. When a user receives invitations by significant others, s/he would be likely to switch to the suggested new MIM. Therefore, the following hypothesis is proposed: