Viral marketing can become an effective marketing technique in social networks. Initiating from a set of influential seed users, it can activate a "chain-reaction" driven by word-of-mouth. The effectiveness of viral marketing lies in the fact that it conveys an implied endorsement from social ties. However, not all viral marketing campaign become successful - some stop even before the number of activated users of the network reaches critical mass. In this paper we propose a new approach to viral marketing that will allow marketers to increase the performance of the stopped campaign by initiating new "waves" of the campaign. But in order to not overwhelm users that were already exposed to the initial campaign, the activation of seeds is performed in a non-intrusive way by suggesting users to follow recommendations of their friends. The proposed method for seed selection for the next "wave" is based on percolation centrality that takes into account already activated nodes and uses their social connections to boost the word-of-mouth propagation that already happens in the network.