There's a good reason for that. If someone's found a profitable niche, there's no incentive for them to reveal information which might attract competitors.
Most of mine has come from a single post about uses for a Raspberry Pi[1].
I've done a lot wrong when trying to build site traffic (multiple domain/url scheme changes, etc) so I think I would be doing much better if I had focused more in the past.
That's a low CTR for that amount of PV. Try putting a large ad right under the headline and lose all the share buttons there since you've got them in 3 other places, it should incrase your CTR quite a bit. http://i.imgur.com/71d9E4U.png
The only site I have Adsense running on does $50-60 a month. That covers the hosting bill. There were a couple of months that the site was doing between $100-120 but that was only for like 3 or 4 months after the launch.
Six figures a year, going for seven (long way away) and compete head on with the industry leaders (they do eight figures). Long time bootstrapped/passive.
