Actually: Gmail is quite the odd one out. They have their own opinion on how to filter, and quite succesful at it. Hotmail and Yahoo both offer feedbackloop and, sometimes, you can contact them.
Now the anti-spam organisations sure know each other, and share data. But on a larger scale that you would probably see in blacklists (for a full list of blacklists:
http://multirbl.valli.org/). Since you are not blacklisted, I don't think that that is the issue.
About the messages: Hotmail says you should try again later. Do that. But Yahoo says that there are user complaints... That is probably true. You may actually be sending too little email (that looks like a botnet-like signature). They want a lot of legitimate traffic per IP, not droplets of maybe-spam.
But to conclude: Email is not easy anymore, even if it is your profession (it is mine). Forget about getting to know what is behind the curtains of blacklists and large inbox providers (they have their hands full on real crime to worry about a few false positives).