Is technical analysis useful?

On October 3:

Charts are certainly great for short term predictions, not because they have any predictive power, but because everyone is watching and trading with them. So largely a herding effect. However, for longer term predictions, charts are much less accurate. If you back test any of the charts, you are unlikely to find anything there, unless you trade every day, which is again based on short term  predictions ;=), and the transaction costs will eat those profits alive.

I have not used charts for a long while now, but I should look more when it comes the time that the bottom might be near ;=).