Effectively, this is congruous to having an "auto shredder" service for email. Rather handy for business use, but if you read the fine print you find out that:
- This is a subscription-based service, so if you use it you will be locked into paying Microsoft for ever after.
- The only email software that will be able to read "IRMed" messaged so far will be Outlook 2003 - and there are not even plans to make rights management work on the Mac.
For another, even for people who DO use Outlook but do not have IRM capabiilties installed (given that they are not free to begin with) it may be a problem to receive "IRMed" email. There is a fix though, if you use Office download the update from Office Update website.