No, you need to buy when everyone has sold AND someone has offered to make a market behind them. That's a very different proposition.
If everyone was selling and nobody was buying, the market would be at 0. It's not at 0, therefore by definition not everybody is selling.
Frankly, I'd wait till Obama makes the call to Mad Money and asks about buy and hold. If Cramer responds " profit and earning ratios are starting to get to the point where buying stocks are a potentially good deal if you've got a long-term perspective on it." Then we got a lock.
Worked just fine for Mr Addams (Addams Family) and Rodney Dangerfield (Caddyshack). I say go for it......
I sure am. Although I have no idea where the bottom is. I'm putting in a tiny bit every pay check, hopefully buying all the way to the bottom.