'Actual Playing Time' - What does this really mean?

[Carolina]

I hadn't noticed this statistic until today when someone mentioned it in the discussion of the US - Ghana match, relative to time wasting. Doing some research, I found it was part of the official match reports in the 2002 World Cup as well, so maybe it's just me not noticing. How is this determined and what is it telling us?

Here are some numbers for some of the teams so far this time around. Only matches involving Brazil seem to have significantly more actual time in play.

Brazil 64,56, 63; total 183
Germany 54,50,54; total 158
USA 58,54,52; total 162
England 53,53,56; total 162
Argentina 57,52,51; total 160

Appreciate anyone's insight that knows more about this!

[unclesox]

I believe it's the amount of time a team actually has possession of the ball, knocking it about. If a whistle stops play or ball goes out of touch, "actual possession" clock stops.
I'm guessing, though.
Serie A has kept track of this for many years. I even remember the tv graphics (international feed) used by RAI during Italia 90 kept track of actual possession.