Microsoft recently attempted to simplify their Shared Source licensing program, but may have made things more complicated instead. Under Shared Source, developers can view, modify and redistribute Microsoft code under varying levels of restrictions. Microsoft claims that the three new licenses will replace and clear up confusion with the older group of ten licenses, but does three really equal three in this case?

The three main licenses are categorized from a least restrictive to a most restrictive version and are called "Permissive" (Ms-PL), "Community" (Ms-CL) and "Reference" (Ms-RL) licenses. Permissive allows developers to view, change and redistribute Microsoft code. In addition, they don't have to release their source code. In contrast, the Community license requires the release of the code. The most restrictive license, the Reference license, allows developers to view, but not modify the source code. This is intended for library or device driver writers who need to know how to hook into certain Windows programs.
Microsoft tries to reduce Shared Source licenses down to three, or is it five? | TG Daily