Give all your money to the poor, and follow me.

[CapnAwesome]

So let start by looking at the word "possession" in the english it means something owned occupied or controled. which could literally mean anything and everything one owns. (which is what you seem to understand this word to mean.)

Now lets look at the koine Greek understanding of the word in a biblical context. the word is:
κτῆμα/ktēma
It direct meaning is the same as the english meaning, but in the biblical context Strong's/thayer's tell us it refers to:
a) of property, lands, estates

So in the biblical context to sell ALL of one's possessions means to sell ones, property, lands, estates. Which Makes one dependant on God for their day to day living. Just like a slave or servant would be.
http://www.blueletterbible.org/lang/lexi...2933&t=KJV
http://www.merriam-webster.com/dictionary/possession

Loopholes for Christ! I'm sure Jesus would approve of you owning several cars and a big screen TV while people in the world starve. After all the ancient Greeks didn't have a word for car or T.V. So it must all be okay.