The title of this Ars Technica piece reads:
Why Steven Sinofsky is out at Microsoft
Concretely, I'm wondering why (if) "out at" is correct – I initially thought "out of" would be the correct option.
I agree that the use of out at in this sense is odd and a tad ambiguous. I suspect that it might be peculiar to American English.
If I had not already been aware of Sinofsky leaving Microsoft, I might have interpreted the above headline as:
In other words, it sounds as if Sinofsky is over there at Microsoft to do something.
The following are random examples from Google books where out at X is being used similar to over at X:
The following are random examples from Google Books where out at X is being used in the same sense as out of X:
There appear to be fewer examples of this sort (which doesn't really say much) and all seem American as well. Perhaps it's a baseball reference?
I agree with the OP that "Why Steven Sinofsky is out of Microsoft" would have been a far clearer choice of headline.