Here is another chart. Declines in net worth drive declines in consumer confidence.
Since some part of Regular Joe's net worth is in the financial markets (via 401k if nothing else), that is another link btwn Wall Street and Main Street.
The other part of Joe's net worth is in his house, and we know what's happening there. Following up on RoninLB's post, frozen debt market -> fewer mortgages. Fewer mortgages -> fewer home buyers. Fewer home buyers -> falling housing prices.
On the positive side, falling oil prices have helped consumer confidence a bit. But that help might be fading. I am, personally, no longer betting on falling oil prices.