To request Microsoft Academic Search API key, I sent this email to acadapi@microsoft.com. I applied 8pm and they replied next day at 7am.

Hi,

I am a 2nd year PhD student at Stanford interested in better ways of visualizing research publications and various links between them.

Contact name: Andrej Karpathy
E-mail: karpathy@cs.stanford.edu

We have read and agreed with the Microsoft/MAS Terms of Use:
http://academic.research.microsoft.com/About/TermsofUseSpecEN.html
http://windows.microsoft.com/en-us/windows-live/microsoft-services-agreement

There is no project URL associated with this request because I intend to use the API for myself from console and for research purposes.

Thank you,
-Andrej

Full instractions from Microsoft are here