I have discovered an interesting article about volumes:

PART ONE

I utilize a lot of different indiors and methods, but the one that has shown me consistent achievement is price and volume in support and resistance. Support or resistance places come at previous highs and lows (that is the reason why inventory and indexes develop trading ranges, they bounce off previous highs and lows). I will show you how price and volume react to highs and lows and why price pushes through or reverses in these factors.
Previous highs and lows in a stock or Index define current support and resistance areas. A low or high in a stock or index is called a swing. I draw a trend line in the previous swing low or high to see at what price support or resistance will come in at in the future. These swing highs and lows are places where decisions are to be created for buy or sell orders. The horizontal lines drawn from highs and lows indie where the support or resistance may arrive in the future.
Sometimes a picture is worth 1000 words. The Line chart of a stock or index below illues exactly what a swing top and low are.
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The following rules I have grown with price and volume came in part with analyzing the functions of the master of price and volume, Richard Wyckoff. Mr. Wyckoff developed techniques from the 1930's that unite price and volume of equities that had price predictability. The techniques he developed stood the test of time and work for this day. I have expanded on these ideas and came up with the principles that I use daily in my trading. In order to keep this article brief, I won't go into all of the principles, but here are some that we can discuss. Here we will view a price background to see where buy and sell signs developed.
Rules whom I follow along with price and volume to see buy and sell signals on the Nasdaq composite and the NYSE indexes
1. Evaluation of a previous low or high on 8 percent or greater reduction in volume and closes back below the previous high (or over previous low) imply a reversal. The market needs to break the low or high and then shut back into the trading range to show the point.
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2. Evaluation of a previous low or high on 3 percent or less in volume shrinkage, imply that low will likely be surpassed.
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3. Always compare volume dating to first high or low; even on 3rd and 4th re-test. The volume buy and sell signal relationship stay the same.
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