Initiated phone conversations and salary negotiation with recruiter before right to represent and then was invited to interview. They usually want to confirm your hourly rate before submitting you to the Microsoft hiring manager. Reference checks matters so make sure you have good references.
I got an offer and was hired with just 2 interviews with their client Microsoft as a vendor contractor after a Skype technical interview for 1 hour and onsite technical interview for another hour. Very few technical questions but mostly skill review. The group at Microsoft I interviewed for was Skype and they ask mostly network related and client server end to end testing questions.