**A: what, that is simply not true. I have used other methods such as carrier pigeon, smoke signal and pony rider to send mail to the IRS.
Let me explain better. The IRS has its own zip codes and their mail goes straight to basically their own post office on each campus. It doesn't really pass through a regular post off to get delivered to them.
Therefore, if you send something that requires special handling, it has to go a different route, and actually takes longer to reach them and longer to get where it needs to go.
Sometimes there may be something that legitimately needs special handling, but most of the time its better to simply send things regular mail. Faxing something that requires urgent attention is usually better than overnighting it as well.