Somebody else recently reported getting no shares credited in their Slush account, even though cgminer was apparently beavering away.  I had the same thing happen a few months ago: the credits suddenly stopped after four days of continuous mining with cgminer.  I switched to BFGminer and have had no issues since.  Notwithstanding the occasional pool glitches, I have had everything credited that I expected.

So I wonder just where all those missing shares were going?  Conspiracy theory, anybody?