I think that's a terrible way to develop a relationship with advertisers. Basically you're telling readers that your advertisers are an annoyance that can be disposed of with a small donation. Content providers and advertisers should be proud of their content and respectful of each other and the value they add to the experience.
Quite the contrary. Advertisers are dealing with growing use of ad blockers due to ad over-saturation and inconveniently placed advertisements on some websites that lead to the watering down of advertising and unintended clicks (for which they pay).
Online advertisers and advertising networks that represent them are savvy. They know that if someone doesn't want to see their ads they'll get an ad blocker if they're forced into it. They also know that if websites provide their users with an option to remove ads and pay for ad-free access, those users won't be nearly as motivated to install ad blockers and never see another ad again
anywhere on the web. Further to that, if someone doesn't want to see the ads, they won't be clicking on them anyways, so the money spent showing this individual an advertisement (for which they also pay) isn't wasted if they take the ad-free route.
Online advertising is infinitely more complex than print advertising. On SSP we use very sophisticated ad delivery systems that deliver the most relevant ads to our visitors at precise times of the day, to precise jurisdictions at a precise daily frequency. These and other parameters attempt to make the advertising experience for our visitors as relevant as possible and as likely to make an impact as possible. We don't always succeed with every single visitor given the volume of visitors from around the world that we host daily, but we do the best we can and it's this that brings advertisers our way and not whether or not an ad-free option is available.
OT but I like the new "your not quite finished with this thread" reminder that has just shown up.
We realized that not all visitors were clicking through to the next page by assuming the last post on a page was the last post in the thread. Glad you like it -- Dylan figured out a way to get 'er done yesterday afternoon.