We're talking about a different type of pool here.  This page describes a two- or three- player variant of the White Wolf's Vampire:The Eternal Struggle, a collectible card game of deckbuilding, resource management, strategy, and trickery, ideally suited for 4-5 players.  The object of the standard game is to remove other players from the game in a clockwise order, by helping them spend all their pool of influence (as tracked with counters).
If you've played this variant, please let me know.
I wanted a two-player variant that, to varying extents:
In the regular three- to five- player game, I'm generally worried about multiple pools (my prey's, grand-prey's, predator's, and/or grand-predator's).  In a two-player game, I'm only worried about one--my prey's.  Since I'm only worried about one pool, there only really needs to be one pool in the game.  And on the flipside of the coin: If there's only one pool, it doesn't really matter how many players there are, as long as the pool is proportionately large. Hence, common pool.
The following cards are not allowed in this format:
Just because there's a common pool doesn't mean that you can't play this variant with more than two people...