I don't know about "on here" because HN tends towards startups and freelancers, but in the US Enterprise sector, Red Hat is what you buy when you want a vendor-supported Linux in your expensive lights-out datacenters.
If you take a look at the Fortune 500, it wouldn't surprise me if Red Hat was in use by at least 490 of them.
If you take a look at the Fortune 500, it wouldn't surprise me if Red Hat was in use by at least 490 of them.