Citation needed.
> I would be willing to bet there is a strong inverse correlation between link size and likelihood of being clicked.
4 extra characters (www.) is a pretty small fraction of the total link length most of the time, when people link to individual blog posts or what have you. I'd argue that readability of the link is far more important, and www does not harm that.
The reason to not use www is in your logs.
> Anecdotally, on my own site of about ~1k daily
> active users, the no-www urls were used almost
> exclusively.
I type in "google.com" every time and don't care that it redirects me to "www.google.co.uk" every time. I don't even notice.
Visitors follow links - just checked netlify.com vs www.netlify.com and over the last 3 days around 0.5% of visits went to netlify.com instead of straight to www.netlify.com
It's generally far more important to setup your site to be as performant as possible and get the best uptime than to skip the the www - there are ways to get the best of both worlds however.
There is real, measurable value to no-www. To anyone here who owns a public website, do visitors mainly go to the www or no-www version of your site? (assuming you don't redirect) Are the short or long versions of your URLs shared more?
I would be willing to bet there is a strong inverse correlation between link size and likelihood of being clicked. Anecdotally, on my own site of about ~1k daily active users, the no-www urls were used almost exclusively. Using www to avoid the rare disaster of DoS is unwise.