Code Smell.

The serious point to this is that trivia questions are all very well but unless its targetted at the job being interviewed for then its useless. It's far better to ask questions in general terms about the subject matter that the job will involve and then ask more probing questions to get at the detail.

Nobody has all of the knowledge that they will ever need to do their job. The best people to have on your team are the ones that can 'work the problem' regardless of what the problem is. A good employee doesn't need to know the answer but should be able to relate to the problem and have a pretty good idea how to go about finding the answers.

No, in no way do these questions say "Yes this person can do the job." But I think general trivia questions are being used to find out if the person is a good fit for the team. I think you can learn a lot about a person by looking at their frequently visited online sites.

For example, most of my coworkers look at me with a baffled expression when I mention a lot of the sites I visit. Though just about everyone I work with is a programmer, I think I'm the only one who has been to Joel Spolsky's site. I'm pretty sure I'm the only one in the company to visit Perlmonks (though there are a few people who claim to know Perl (I say claim because I've shuddered at some of their Perl code)).¹

I spend a fair bit of time online, I like to work with others that also spend a lot of time online -- or reading. If I say "Pragmatic Programmer" I expect that a programmer should have some clue what it is (and hope that they've read it, but my personal reading list is already huge, I can only read so much in a day -- so I can understand if they haven't read it).

¹ Update to add: I'm not claiming that visiting Perlmonks is a prerequisite for knowing Perl. Nor is visiting Perlmonks going to indicate that you know Perl. But having some vague notion of the things that I find to be very common online is a definite plus.