The rule was seemingly put in place after discussing it with dogie, who if your not familiar with created a ton of the original "How to for Miners". Which was without a doubt very useful information. There were also some examples of threads that were deemed not worthy put forth by ..... ummmm ..... well you can read it.
To add some context, there was a discussion around the time I considered publishing on CoinDesk instead. They would have paid me, while the forum obviously does not. Similarly, I could have self-hosted (which I do, just as a backup on dogiecoin.com) and directed forum traffic to there, but that too seemed like a sub-optimal option.
I was merely looking to cover basic costs, and so discussed with Theymos about a revenue share on the forum ads shown on my threads - which wasn't insignificant given the traffic and CPMs back then. He decided it was easier to allow me to inject some of my own ads into the threads.
I'd have to check on a $ figure, but they didn't really make all that much IIRC and eventually, it wasn't worth the continued hassle of running the auctions, updating 30+ threads every 10 days, or the hassle some members would give.
