Student & Teacher Edition is much different. That one i believe is still allowed. But anything like Standard, Pro or Ultimate can not. S&T is still allowed because it is used mainly in a school environment. Which helps the schools out so that they do not have to buy a copy for every PC. They can get a certain number of copies to cover all the PC's.
The licensing has changed since OfficeXP. Mainly with Office 2003 it started cause of the high piracy. They even went as far as having a WGA for Office but later got rid of it.
