I'm guessing that the 22,687 number includes li##-##.members.linode.com. So the actual number of physical hosts is much less. Also, if each host's revenue is roughly $800/month (40 360's), using the 22,000 number, it would mean that Linode rakes in about $217,800,000 a year. This seems a bit high. Using my number of 502 hosts, I get $4,800,000/year, which seems to be a much more reasonable number for a company with 6 employees. Of course this is all speculation. And I seriously doubt they'd publicly say how many servers they have.
Oh, and they seem to have disabled AXFRs after your post. Or atleast blacklisted my Linode from AXFR-ing
