It is my opinion that any research behind a paywall does not exist. If I told you that I have research that showed some effect X, but there was no way for me to make that accessible to the public, no one would put any weight at all behind it (well except for those who really want X to be true). Does it matter if it is a pay wall or if I promise it exists and my girlfriend up in Canada, the one who only visits when you aren't here, has it? No, not really.