The use of Living Labs is gaining importance as an approach to involve users in innovation and development, serving to make users active participants in the development of the networked society. However, Living Labs are currently not taking full advantage of online applications to support user involvement, even though such applications are gaining impact in other fields of innovation. The purpose of this chapter is to: (i) present a framework to classify and relate online applications for user involvement to the Living Lab context and (ii) present a set of guidelines for the usage of such applications within Living Labs. The framework and the guidelines are the results of a collaborative process involving seven Living Lab researchers from four Nordic Living Labs and are meant to guide Living Lab administrators on whether or how to use online applications for user involvement. The framework and the guidelines might also be useful for the designers of online applications.