Was employed by a large bank in their web division. We fixed many Y2K bugs that would have been triggered. Was on duty New Year's eve and there were a few Y2K bugs that surfaced but nothing show stopping. My anecdotal opinion is that the panic to fix these bugs likely prevented some larger cascading effect/catastrophe. Remember, this was 1999 when testing/QA practices were not always de rigueur. For some shops, Y2K mitigation might have the first time their code base was subjected to any sort of automated tests :-))