Here is an example of such a Quadrant, using made-up products:
Of course, being inside, or outside, of the Quadrant doesn't mean ANYTHING to me. I'm not evaluating here the veracity of the Magic Quadrant, just its purpose. When choosing software, I prefer "going with my heart" when I can.
But there are cases where using the Quadrant can be of help. For example, if I happen to like Gorbatcheck and it turns out that it's favorably placed in the Quadrant, that's another thing up my sleeve that I can pitch to management. It's also a good ticket to my own peace of mind as being backed by Gartner gives a sense of immunity if the product turns out to be below expectations.
There is also the case where Gorbatcheck might be based on an open-source product, let's say Gorbrafree. Of course, Gorbafree won't be in the Quadrant, but the Quadrant can be used to give more credibility to Gorbafree over something less stellar such as GZK. If you're on a tight budget, that's a way to introduce Gorbafree until you're ready to move on to Gorbacheck.
How do you obtain these quadrants? Try Wikipedia!