You may want to consider running a website like a news website or anything that writers can freely make an article then you would put some adds on it that is each time someone visits you will receive some income passively or you might try to run gambling websites or what. Also you can try investing like in ethtrade.org or you can invest in Bitcoin itself or other promising coins. All you need to do is to update yourself so you can decide whether to continue or not.
And why would the writers put an article on your website? Of course you'd have to pay them because otherwise your website would have no attention at all. With that, get ready to people copy + pasting articles from another website just to get earnings from your website. Another one, get ready for people spreading FUD if ever your website gets enough traffic for fudsters to post their articles at. There's not that much earnings on putting Ads on websites nowadays since most niche are already taken.
With a very low earnings, you'd have to give a part of that to the article posters. Meaning, the article posters will be earning dusts or almost nothing at all. No one's going to put up for that since there are article posting websites out there that pays well. You're gonna have to write your own article and in no time you'd ask yourself if it's really worth doing.
Have you heard of diply.com? Also it is like using facebook which people doesn't actually paid for posting but rather they just post because they want to but the owner of the website does earn through displaying some advertisement. And another one is websites that let you watch animes like kissanime.com which offers high quality animes and earn passively through displaying some advertisement. I'm not saying that he will earn greatly about it but he can earn passively.
Though it is like a side job for the website owners since they have actual thing they do in their websites but it is a great way earning a passive income while earning a decent amount of money in other ways. This is a great way really.
P.S. If you have read the person whi started the topic, it says he wants to earn passively and steadily with "small & secure" rather than "big & risky."