I must admit, Boxing Day was not on any Y2K list of problem dates I saw.
Judging by the interview on the news last night they basically
said that it was a date issue but not one pertaining to the
Year2000 issues, and that the same bug could have happened
1998 -> 1999 roll over.
Neil.
Although not exactly "network" related, another issue which
is not directly related to Y2K, but potentially troublesome
for some users nonetheless, is the fact that older versions
of browsers contain some digital certificates which expire at
the end of 1999, introducing potential problems with conducting
electronic commerce transactions beginning Jan. 1.
http://www.zdnet.com/pcweek/stories/news/0,4153,1018428,00.html
- paul
We've been through this one before, as we use Thawte certs for
ourselves and our customers. There are still people out there using
browsers with old certs, and of course the customers come back to us
and go "verisign certs seem to work, why did you sell us one that
doesn't?" - the usual "i don't care if it's the browser at fault, i
want one that works with faulty browsers" situation 
Unlikely to actually introduce any real problems, but will flash up a
few warning messages about untrusted certs (the error message most
browsers produce is always misinterpreted by the user).
Not a serious operational issue, as such, but almost certain to induce
some minor hysteria with lusers of a more nervous disposition.
My greatest admiration goes out to the divots who timed them to expire
during the Y2K rollover, though! Well done chaps!