I also explored this issue and confirmed my own opinion on this matter. The best way is to organize a bonus campaign by your own, but in order not to lose the main focus, especially for the lack of a person in a team that could conduct this program, it is better to hire someone for operational tasks... to check the posts, articles, translations, communicate with participants, publish the relevant info about program and so on. This will cost much more cheaper than to hire cool manager for project promotion and will save time for the main objectives.