Major Skype outage "not caused by a crash"

dhollist writes: According to Skype's website their system "has not crashed or been victim of a cyber attack. We love our customers too much to let that happen. This problem occurred because of a deficiency in an algorithm within Skype networking software. This controls the interaction between the user's own Skype client and the rest of the Skype network."

What is the difference between an outage where nobody can access the system and a crash? If my desktop computer locks up, but I don't get a BSOD, did it really crash, or is it an "outage" since I am merely unable to do anything? Is there truly a difference, or is it just semantics? An article in The Sydney Morning Herald provides additional information.