Wow.... hmmm. My suggestion is simply that given that for the majority of the people reading this site process by reading left to right, english speakers. By having the ads on the left it break the concentration of the user and while possibly giving a short term boost in ads, could result with a long term frustration with users.
I'd rather ads on EVERY SINGLE page then on the left of the screen. I don't WANT to block ads, I even supported the forum even though I don't spend a ton of time here because I love what you guys do. I actually click ads when they are relevant. That said, I'm especially surprised by the callous nature of your reply.
If ad placements damage the readability of a forum, I think it says enough that I care enough to mention it rather then simply looking for another forum. I'm gonna take the high road and assume you're just having a bad day or something....