The Pobox spam slider uses Pobox Recommendations to help you customize how much mail we block for your account, easily. The categories are:
Weak (catches approximately 70% of spam): We only apply our most accurate filters (less than .01% are legitimate mail, or 1 in 10,000), and hold all messages. This is only recommended if you are extremely tolerant of spam, and extremely intolerant of delayed legitimate mail.
Standard (catches approximately 85% of spam): We apply all our accurate filters (less than .075% of messages are legitimate mail, or 1 in 1,350.) We hold all messages. This is our recommended setting for new users.
Aggressive (catches approximately 95% of spam): We bounce mail most likely to be spam (from our accurate Standard filters), and hold messages caught by our more aggressive filters (less than .25% of messages caught are legitimate mail, or 1 in 400.) This is the best level if you have been using the spam filters for more than 2 weeks and would like to reduce the amount of spam to review. We recommend using standard for at least 2 weeks before switching to aggressive. This gives you a chance to review any legitimate messages our standard filters may pick up for you.
Very Aggressive (catches approximately 97% of spam): We bounce mail caught by standard and aggressive filters, and hold messages caught by our extremely aggressive filters (.25% to 1.25% of messages caught are legitimate mail, or up to 1 in 80.) This is only recommended for people who are very fanatical about spam.
Trusted Senders Only (should catch all your spam): Only messages sent by people on your Trusted Sender list will be delivered to you. All other messages will be held. This is only recommended if you have a substantial Trusted Sender list.
In addition to these categories, we also have a Pobox Hotline, which is automatically applied to all accounts. If our monitors detect a spam attack going on, the sender, domain or servers delivering the messages will be added to the Hotline. Messages caught by the hotline are automatically bounced, even if you are using Weak settings. Because this detection looks for a large volume of mail going to a large number of Pobox accounts, the hotline should never result in legitimate mail being blocked.