Just did a surface audit.
They set and read no cookies. You can test this yourself.
They set etags on static assets, and those theoretically could be used to track you as an identifiable visitor.
How else would they track you? By IP address? That would make any kind of tracking useless -- how would you deal with trying to track 100,000 connections from behind NAT, individually, other than cookies or etags?
There's browser fingerprinting, but I don't see any evidence of that either.