Honestly? Signature ad campaigns on this forum.
If you have full stack coding skills, there may be more profitable ways to earn btc
I would agree with your comment about signature campaigns. Although bitcoin is very much money, the value given to advertisers is real and advertisers on here tend to have income in terms of bitcoin.
I think most of the people do not understand that bitcoin is money, and you would do the same thing to earn it, like you would do for fiat.
However, a lot of people don't like going through exchanges, and the complicated things to buy bitcoin, so they think of alternate ways to get it.
And it is then when things like signature campaigns get counted.
Well I think the question would be better phrased if it were to include some kind of clause that asks how to get paid in terms of bitcoin. Microsoft and Apple for example both have costs in terms of fiat based dollars so working for either company would not be a good way to to earn bitcoin as the amount you would earn would vary based on the exchange rate. On the other hand a bitcoin dice site has the majority of their costs (and income) based in terms of bitcoin so working as a developer (or otherwise working) for a dice site would be a better way to earn bitcoin in terms of bitcoin, regardless of where the exchange rate goes.