Solving for Private Message Abuse

Hey all,

My team is thinking through whether to permit private messaging in our community and could use your input. We would like to encourage members to connect and collaborate with each other and think private messages can help with the coordination of contact info and logistics for offline engagement. Our challenge is that we are worried that influential or popular users will get inundated with private messages and elect to ignore their inbox and notifications altogether.

Has anyone tackled this or a similar challenge with private messaging with a recommendation to share?

If there was a way to restrict private message permissions to only members who follow each other (think Twitter) enabling private messages would be a great value-add to the community. Your help on this would be greatly appreciated!