Wisdom of the Crowd or Mindless Cattle?

It seems I'm always seeing ads proclaiming an auto as "the most popular car in America" for XX years running, as though that somehow automatically means it's better than the competition. I've never bought into that myself, as I'd rather do my own research based on my own criteria than trust the opinions of countless unknown strangers. But the ads must work, because we keep seeing them.

I only bring this up because we see the type of people at the library who must surely be the target audience for those ads. They'll look on the shelves for books and movies if they must, but they'd much rather look on carts of recently returned items. Even better are items in the hands of librarians. They don't even need to take the time to read the summaries on the covers or know anything about the items--as long as others are reading and handling them, they are automatically better than anything sitting waiting to be discovered.