Linus went to the Osberts and met various celebrities he couldn't identify.
Puts me in mind of the first time I attended Making Orbit (a space-access convention). Failing to spot the registration desk, I (rather brusquely) buttonholed a pair of obvious convention-goers to ask where registration was. A couple of hours later, I found out the people I'd accosted were Poul and Karen Anderson.
Yes, I know perfectly well who some of these people are by name; I'm just really bad at matching faces with the names.
Heck, if I met Linus, I wouldn't recognize him without an introduction.