Why does quantum foam produce virtual particles

You have it backwards.

John's answer is pretty good.

My understaning is "quantum foam" is an extension of Wheeler's "spacetime foam" and "it from bit" ideas.

There are many different ways of looking at this problem.

I tried talking about a related situation with Jocob Bekenstein recently and felt a bit of an idiot afterwards because my explanation was totally different to his. Just as their are many interpretations of quantum mechaincs so there are many different understandings of what causes and is happening with quantum foam. I use a system similar to Raspanti's Virtualism that inspired the movie "The Matrix".

In my model digital rounding effects cause the uncertainty or foamy fluctations.  

On Benji Bear and Friends I talk a lot about related issues to this question.

See http://benjibear.com

MofAllSelf, please disregard McCann entirely as he has not one clue about science.

Gromwald seems to have read the Wikipedia article but still lacks a clear understanding.

Let's begin and try to unravel this mystery correctly.

First, let us find your level of understanding of:  Minkowski Space, de Sitter Space, Anti de Sitter Space, and subatomic string theory (we will leave the dissertation on M-theory for subsequent discussion).

It will help that you understand a bit more about space-time and mass-energy interactions than you will receive on the Science Channel.

Please contact me with your current level of understanding and we'll go from there.

Let's start QF with a correct understanding of what space really is.  Space is not merely a vacuum.  Space is a quantum field wherein gravity has a repulsive function and energy becomes either dark or light (that requires a discussion) which gives gravity an attractive force. 

This is no small discussion but let's look at some other work that I hope will clarify.

http://arxiv.org/abs/cond-mat/0404617

Let us consider 11-dimension spacetime a uniform field.  Our Lorentzian11-dimension constant is approximately equal to G^2/3, which gives us sufficient mass in our spacetime for particles to "grip" space and move "charge to charge."  This also satisfies the basic Hamiltonian h(1)^-2/3 + h(2)1/3.

 therefore violates powers of zero in a state where stasis applies:

The simplified diagram above shows the energy-reflex opposition of Minkowski v: de Sitter space, unifying both @ L^-2/3.