I have an idea for a website that will attract many visitors.
I will need to put a lot of effort to build it,
but then it will run (almost) by itself.
What will be the best way to convert it to some passive income?
Advertising? Affiliates? VIP registration?
How much should I expect to earn from it?
I am no expert but this is very lacking to me. What kind of website do you have in mind? Who are your target clients? How do you intend to increase traffic to your website? What is in your website that companies or other sites will have their ads posted in your website? There are still a lot of questions to be asked. But yes, ads is really good and passive source of income.