Microsoft trying to hijack a term with an already fully established meaning is dishonest and screws up everything. This may be an honest mistake by an employee that fell for Microsoft's own marketing, but it's still not right to spread misinformation. Is the license on this list [1]? Then it's almost certainly not open source. Also, this particular license has already been rejected by OSI.
The GPL is not the only open source license. It may screw up certain commercial usage, but it never stops users from forking the software. This
Microsoft license does.
Er, technically this license doesn't stop forks -- they are explicitly allowed -- but it definitely propagates the non-commercial clause. I agree, it's definitely not Open Source.
I meant that it doesn't allow arbitrary forking. There are cases in which it's illegal to keep using it, whereas with the GPL at most you'd have to release the derivative source to your (paying) users.
The GPL is not the only open source license. It may screw up certain commercial usage, but it never stops users from forking the software. This Microsoft license does.
1. http://opensource.org/