TBH, I stopped reading it because I really do not like the font used on the website.
“It appears that this website bought the rights to publish this article from the author.
The original article appears to have been posted on the author’s blog quite some time ago: https://ooomf.com/blog/the-science-behind-fonts-and-how-they...
As such criticising contradictions between website design and what the article advocates makes even less sense than it usually does.”
Since the majority of internet users have much less pixels per inch as compared to the retina, I think it should be best for websites to use san serif.
However, the historical reason why sans-serif are generally recommended over a serif on a computer screen was a matter of practicality. The computer monitor simply couldn't replicate the tiny detail required by serifs. Higher resolution screens are becoming more common place, which is why you'll see more serifs in use online (IMO... correlation vs causation and all that). Somewhere along the line someone cited scientific articles to help justify this practice, but I'm convinced it became common place was really for practical reasons/aesthetics more than anything.
[1] I haven't personally done a literature review, but this post is great in discussing the conclusiveness around the research (and readability vs legibility vs....) http://alexpoole.info/blog/which-are-more-legible-serif-or-s...
Here's an interesting anecdote I just remembered, though. A psychology professor of mine was attempting to replicate another researchers work. The result couldn't be replicated when the stimuli was displayed in sans-serif fonts, but it was replicated when they finally used the font the initial researchers did: a serif.
I'd bet serifs/sans may have some sort or psychological implications but I doubt it's as straightforward a relationship as often presented