There are people who will stop liking something once it becomes too popular. It is like reverse peer pressure. It seems strange, though, kind of like saying, "oh I used to like the taste of chocolate, but then I found out that millions of people like it, so now I don't like it any more. In fact, now I only eat pickled rabbit noses, because they're not trendy."
What if your favorite band became really popular, but you didn't realize it? Then would you still like them? If a band sells out in the forest, and nobody is around to hear, would their fans make a sound?
What if something were really popular, but nobody knew it? This sounds like a contradiction at first, but it could happen. A web page without a hit counter could become secretly popular. Or if the hit counter were broken and always reported a very low number, every visitor might be fooled into thinking they were among the "lucky few" to have discovered the page.