I just read about this over the weekend in John Kenneth Galbraith's book The Great Crash. The ticker tape machines were about 3 hours behind in most parts of the country and that caused a massive sell-off as people tried to get out of the market even though they did not know the current value of their stocks.
I wonder how long it took to see the sell-offs before the subsequent collapse in the 30s?
EDIT: I didn't mean to imply that we're near a depression. I was think about how technology helped us. Thanks makaimc.