When anything new comes into place in the work environment, some employees will be hesitant to adoption and adapting. Because they're not entirely dependent on this new movement to get their work done, they might not see the urgency or necessity to learn the new ropes.
My idea for a feasible way for employees to adopt and use enterprise social networking platforms is to integrate the actual day-to-day work into the platforms. This method prevents employees from avoiding the social networking platforms and consequently learn it if they want to get their work done. Of course there will be mandatory training sessions and the executive leaders would have already started to use the platforms to communicate with their employees about any work-related matters. All internal communication should be done on this new platform, as well as exchanging any work-related documents.