These pay-per-click ads appear on your blog. Every time somebody clicks on an ad (which is supposed to be about a subject related to your niche), you make a few cents or more. Small amounts each time, but it adds up. This is extremely hands-off. You just need to get a code from Google, place it on your website - and the ads will automatically appear on your blog. Google will only show ads that are relevant to your blog so it's a good experience for your visitors and maximizes the number of clicks you get, meaning more income.
I like these ideas! Besides being good ideas in themselves, they stimulate MORE ideas! Some of them reminded me of something I was reading about called Craigslist arbitrage – buying low and selling high on craigslist, kind of like the first part of the old Oregon Trail game, but with washers and dryers and bicycles instead of cases of crackers and horses. Sounds like fun!  Anyway, that one about the pooper-scooper business, that works, I know because I was quite successful in the pooper-scooper service I started back in 1988! I’ve been in the industry for 25 years now, though I don’t go out and scoop any more.
The internet changes so fast that one year online equals about five years in the real world. But the principles of how to start and grow a successful online business haven't changed at all. If you're just starting a small business online, stick to this sequence. If you've been online awhile, do a quick review and see if there's a step you're neglecting, or never got around to doing in the first place. You can't go wrong with the basics.