The COT data is very valuable for longer term traders ... if you take the time to study and understand it. Each market behaves slightly differently, as do the behaviour of the 3 players reported in the COT data.
It is not valid to make sweeping statements like the commercials are always the side of the market albeit a little early. Some futures markets are actually used for hedging by the commercials and they consistently take a beating, eg: Nat Gas.
Somebody mentioned Nat Gas earlier so here's my analysis for this market....
Small Spec
These guys are always net long. Since 1991 they have been net short only 1 week (Dec 2001). Their positions are very stable which suggests there is very little speculative retail money in this markets - ie: dentists do not have the scrotal fortitude to play this market. In the last 5 years their short holdings have remained constant but they have gradually added to their long positions. Possible impact of the emergence of long only commodity funds. Because of their long bias they make money during rallies and give it back during selloffs and sideways markets. Overall they don't do much better than break-even.
Large Spec (Trading/Hedge Funds)
These guys generally make money in this market. They take money off the small specs and commercials. They had a long bias up to 2001, but since then have definitely favoured the short side. They were net short during the recent explosive rally - got killed obviously. Their positions are alot more volatile than the small specs and commercials, in accordance with the market action.
Commercial Hedgers
These guys have a definite short bias. In fact whenever they get net long it is time to buy Nat Gas. Over time they lose money - they are hedging their forward requirements. Their positions have remained vitually unchanged for 3 years.
Bottom line: Nat gas is a traders market. The regular explosive moves are not the result of a sudden increase in buying/selling interest - it is probably driven by interests in the pit.
Heres my recent charts on Nat Gas and COT data.
Combine COT data with seaonal analysis and market action and you will get 2 to 3 low risk high reward trades in most markets every year. Enough to make any patient, pragmatic tradre rich beyond belief.