Hello, I asked myself the question and have even tried the following thing: not to use keyword-optimization for SEO. And it even worked out well on some niche sites! I'm not sure if anyone tried this... what is your opinion? I assumed that certain niches, certain subjects, issues are popular and I built sites around them: all I did was to check some keyword count, Google trends and then build sites without optimizing... I simply wrote the content "as it came"... I used tons of synonyms, varied words a lot, tried creating quality content without any SEO juice... And perhaps this exactly what scores well in LSI... I'm not actually saying this is what has to be done... I just tried it with a few sites and it payed off much better than with the sites that I optimized... Your ideas, opinions? Experiences?
I think that is how it worked: you wrote the content "as it came to you", using synonyms and related words within the content. Related words and synonyms increase the relevance of your article to its target keyword. Still, it's best to have a target keyword in an article so that you know what keyword you're targeting for each of your articles and what you want to rank your pages for. Hope that helps. Have a good day!