$20,000 In 1 Month at 20

There seem to have been quite a few posts recently about people making good money from their own business on HN. They seem to fall into two categories:

a) SaaS products

b) online marketing

The posts about the later seem to be more popular. I'm guessing because it is a lot easier to make a quick buck with online marketing, however the results also seem to be less sustainable. I'm getting the feeling that a lot of this is down to luck. As I understand with a SaaS product, if you manage to make $20k in a month, you are probably able to do pretty much the same the next month. It doesn't depend so much on choosing whatever is a profitable niche that month and how well Google ranks you.

Anyway, I from this I have two questions / requests for posts:

a) Has anyone managed to sustainably get income from online marketing?

b) Has anyone managed to make a quick buck like this from a SasS product?

I don't mind the recent 'Passive Income Hacking' posts but I am not sure what this is doing on the front page, and why it made it there so fast with such a linkbaity title. flagged.