That's the problem, because anyone can contact you the most sensible thing is not to display your email address but with a system like this or something similar

That's the problem, because anyone can contact you the most sensible thing is not to display your email address but with a system like this or something similar that could change for the better because usually when you email someone you want something, and in most cases your willing to compensate that person for their time. Take for instance a finance blogger, you could possibly send an email but then most people are already doing that so currently you don't stand out but if you think that person's time is worth $50 you could pay that person an incentive with the hope of getting a reply, no reply then you get a full refund. Currently email and the internet in general don't place a value on people's time, but that's changing because Google can't provide the answers to all our questions - sometimes the experts opinion is what's required and it's time their compensated, it's only fair.