Good point. Some other forums have ad banners repeating between 3 or 4 message posts. to give their sponsors maximum exposure.
If there is granular control over ads, could fee-paid members just have them at the top of the page?
For the last ten years or so my firewall strips out all ads that are not hosted on the same domain as the website. I have just noticed that I don't see any ads on the existing site either. This may also be true for others that use browser extension ad blockers.
Before I buy parts I usually look at the sponsor page and click through to their websites to look for deals.