Blogging based on bitcoin or cryptos can help to earn bitcoin if you show crypto-based adds.
That's a pretty good idea. Blogging with crypto really works well nowadays, as people are getting interested into crypto so making blogs with good SEO work can really help for making money. Therefore I have seen many projects hire content creators to write articles about their project, so that can be extra income for crypto bloggers/vloggers.
Agree, content creation and blog about the project is a strategy that projects are all looking forward to in the bounty strategy, with demand still quite high, this could be considered a way to earn bitcoin in 2020, if we don't have many creative ideas, the signature campaign is also a small part here, we can try with such projects. But the general market for making bitcoin through free methods is no longer optimistic, we should learn more about trading with currency pairs, this path seems to be better, gaining experience before the free money path ends.