More Microsoft lies In this article, Zac Woodall, an Microsoft engineer, says

"We of course have a policy on GPL code: we can't look at it. What is the reason for this? Well, in my read of the GPL it states that if a work includes GPL code, or is derived from GPL code, then the GPL applies to the aggregate work. And it is very hard to discern between which ideas are completely yours, and which are influenced by code you have seen in the past. What this means is that by incorporating, or possibly even reading GPL code, you are placing your own IP in jeopardy. It seems to me that anyone producing commercial code should be very careful about the implications of the GPL on their dev processes."

Zac should read the GPL again. Such restrictions on use only apply to Microsoft code, where reading it makes you liable for any implementation of any features you ever write for the rest of your life. Software patents work the same way by shutting down innovation entirely. OTOH, the GPL does not require you to sell your soul if you look at the code, Microsoft's licenses do.