In the context of Mobile Ad-hoc Networks (MANET), we study the problem of disseminating a piece of information, initially held by a source node, to some subset of nodes. We use a model of MANETs that is well suited for dynamic networks and opportunistic communication. We assume that network nodes are placed in a plane where they can move with bounded speed; they may start, crash and recover at different times; and they communicate in a collision-prone single channel. In this setup informed and uninformed nodes may be disconnected for some time, but eventually some informed-uninformed pair must be connected long enough to communicate. We show negative and positive results for different types of randomized protocols, and we contrast them with our previous deterministic results.