It's classifying retail investors and their money flow. Not that retail investors are dumb, but that they're traditionally less sophisticated than, say, Warren Buffett.
We can track money flow by following ETF and mutual fund flows, small lot trades. He pitches that against people like Warren Buffet, Teachers' Pension Plans, and commercial hedgers. Those would be the smart money. When the two are at opposite ends of the confidence levels of who's selling and who's buying, he has leading signals that say perhaps we need to be cautious or we need to be aggressive. If dumb money's selling and smart money's buying, maybe he needs to go in, or vice versa.
There's evidence to show that retail investors get it wrong more often than the pros. He's even written a book on it. There are lots of indicators to look at, like the put/call ratio and the VIX. So when retail investors are bullish, that's a bad thing; and when they're bearish, it's good.
Again, these are leading indicators. When big money is selling and getting out, you want to follow the smart guys. There's a point when they're going to start buying again. When retail people are bidding up, it's not a bad thing since it pushes the market up. But at some point, you hit the point of Greenspan's "irrational exuberance".
Yes, their confidence levels are lower. It's a leading indicator. Doesn't mean that tomorrow the market's going to fall. But it does mean that the market's setting up for a correction, whether it's next week or 3 weeks from now. He's put some charts on his blog, valuetrend.ca.