Set your limit orders folks. VTI
Probably at big locations. Many large companies run leased lines (frame relay, etc) to their processors. Many don't use the public internet at all for those connections. Obviously, ecommerce will be boned.
Small businesses use internet for transaction routing. Large businesses tend to use direct lines to their processors that don't use public internet. There are also offline processing options. It'll be messy but some places will still be in business.