I have a website with ads on it. Or actually a few, but one that mostly pays for my life right now.
The only "secret" other than user generated content (what makes it actually passive) for me is to never stop trying. I have like 50 in use domains right now, many which i did not extend because they did not pay for themself after a year.
How do you source your user generated content? Is the big earner a forum or the like? I'd kind of envisioned some kind of static sites with ads.
Have you taken a noticeable hit like others in this thread from diminishing ad revenue and rates?
Its more like a forum, but not one. Users can post their own content and others can vote and comment that. Plus it has a huge searchable database.
The problem with static sites (i have those too) is that google loves site updates as often as possible. A site that is good ranked today can be killed by a more dynamic one next day.
Most of my other sites are more on $50 - $200/year too :/