This sort of sounds like the Steam Hardware Survey. They do not collect the data willy-nilly, they ask you every few months if you want to participate in a one-time check.

I have an incentive to see if the Linux desktop share has increased, so I usually run the survey for them to get my data point in. I also suppose the "gamer" crowed likes to show off how powerful their "rig" is, so I would imagine they commonly also run the survey for that reason as well.