Mini-Microsoft is the name of a blog maintained by an anonymous author who appears to be a Microsoft employee. The term is also generally used as a pseudonym for the author of the blog, although on the site the author is listed as "Who da'Punk". The nominal goal of the site is to shrink Microsoft down to a smaller, more efficient company, but Mini-Microsoft has become a place where Microsoft employees and others engage in an open discussion about all aspects of the company and what it is like to work there. The site is credited with providing some of the impetus for internal changes at the company in 2006, specifically concerning how employee reviews are done.
I was first made aware of this blog when I worked for a Microsoft vendor and it was a great insight into some of the internal workings of such a giant company and not oft heard internal dissent.