Great article, I have tried a few over the years. I had a side business cleaning offices for years. It did great, but I hated never being able to take more than 3-4 days vacation, so I eventually gave up. I tried MTurk, but if you multiplied my earnings on an hourly basis, it was a little over $6/hr. My blog is much worse, probably less than $0.25/hr.
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One of the cool things about Google AdSense is that it's so easy to get set up. If you have a blog or website, you can sign up for a free Google AdSense Account. From there, Google will give you a unique code that you will paste onto your website. Google takes it from there, tracking your page views, traffic, and earnings on your behalf. There is no upkeep or maintenance to get this thing going, which makes it a no-brainer if you have a website already.