When you are "giving your address to the public" -- you are typically only doing so with the intention of receiving responses for a limited period. If you think about it, when you fill in a form you typically only wish to receive replies immediately, not three months later. The same applies to the Usenet: when you post an article you are only really interested in replies prior to the article's expiry.
This is where the concept of Temporary Addresses comes in. Mailtraq now supports the concept of an e-mail address that has an explicit expiry in it.
Concealed addresses are in the form user$E60@domain.com and must be sent through Mailtraq. In the example, the 60 is the number of days from the current date during which the address is valid. When Mailtraq receives a message sent from an address in this format (at one of the local domains) it converts the address (and every occurrence in the message) into something like E-123456789ABCDEF-123-E@domain.com thus completely concealing the original user part. When messages are received addressed in this format (to one of the local domains), Mailtraq will decode the address and verify that it is within the validity period. If not, it rejects it (as for Explicit Temporary Addresses) otherwise it converts it into the original format and allows it to continue.
Using Concealed Addresses
You should use the Concealed addresses when you are able to send an e-mail or Usenet article through Mailtraq (giving it the opportunity to conceal the address).