If people in NN are ignoring questions to just talk, I'd actually consider filing a report on them. The reason to be in NN as a mentor is to answer questions and is the only requirement listed by SE via the game. If they're ignoring their only obligation, well, that and inviting new/returning players, they don't deserve to be there. Failing to fulfill their obligation runs the risk of being stripped of mentor status, as is outlined in the game whenever you rejoin NN as a mentor.