In the following video, Motley Fool One analyst Jason Moser takes a question from a Fool reader, who asks, "On MSN Money, I noticed Volume and Average Volume. Volume changes by the minute ... is this volume stocks on the shelf for sale, or is it stocks that have sold? How can I use this to know to buy or sell? Please explain this in layman's terms."

Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.