Ask HN: Service that blocks new inbound emails from unapproved senders I had seen a service in the past where, if you're emailing me for the first time, it asks you to do one of two things: 1) verify that you know me by answering a simple question 2) make a donation to a cause I care about so your email goes through I'm pretty diligent about unsubscribing from all the crummy business newsletters I somehow get signed up for, but am looking for something a bit more aggressive. In short: I'm looking for a service to keep out all emails except for the few senders I care about |