SPF and SOHO privacy
SPF (Sender Policy Framework) is cool stuff and when implemented properly helps vanity domain owners play on par with big email service providers, like gmail.
However, in its basic form it presents privacy concerns for small offices operating out of their homes, or any other small mail senders.
The problem is that anyone on the Internet can look up a list of IP addresses allowed to send mail for a given domain. Some users may feel uneasy having their home IP address known to everybody.
Here is how this issue can be resolved while still reaping full benefits of SPF.