Something that I can actually see is:
When you click a link to view another site, you also send a 'referrer' with it.
So, when people click on my linuxtips.gq site links, they send a referrer and those are logged as part of the site's metrics. (Every site does it, even this one.)
The majority of clicks come from people using the www.
About 3:1 use www and not just linux.org, according to the very limited numbers I have available. That also includes only the people who have clicked links to the linuxtips site in January. (Approximately 60 data points, so a very trivial amount and shouldn't be used for more than wild speculation.)
I am a bit surprised by that. It's easier to just type linux.org.
I actually am at the www subdomain, 'cause I clicked a link in an email and just haven't switched it - as I leave the tab open by default.
Anyhow, if you want to WAG and speculate, 3:1 use the www subdomain.