It's free, and takes less than a minute.
Use Reachmehere to limit the useless messages you receive. If one should make it into your inbox, atleast you get paid for it.
Good messages do really come by every now and then, so one should not be completely unreachable - but not be reachable by everybody.
It takes less than 2 minutes to accept messages on Reachmehere. Just complete these steps.