I had a site with some traffic and a popular, class-leading ad plugin for the platform.
At some point I just lost interest in the whole thing and cancelled my plugin subscription.
I got an email from the developer, which was kind enough, asking me why I was cancelling and if there was any feedback I wanted to share.
I mentioned how complicated ad inventory, ad placement, and online ordering for hands-off customer self-service was.
His question back was, "What's hard about it?"
I couldn't even muster a reply.