From TechRepublic:
When eBay’s clocks failed to jump forward an hour in 2001 to reflect daylight-saving time, the timing on auctions ran into snags, prompting some head-scratching from sellers and bidders.
At the time, eBay blamed the glitch on a bug in Microsoft’s Visual C++ code. Microsoft had released a fix.
On Monday, President Bush signed a sweeping energy bill that will lengthen daylight-saving time by four weeks starting in 2007–raising the possibility of a smaller-scale repeat of Y2K-like problems.
For most computer users, the effect would likely be an inconvenience at worst: Their computers will be updated with new software by then, or configured to connect to network time servers that will know the correct time. But because not everyone’s computer is networked or updated, some glitches could occur–especially in consumer electronics devices that aren’t designed to be reprogrammed.