Why are some pages attractive then others?

Why are some pages attractive as the others? The question that I get to almost any meeting or coffee. The only correct answer is because they have more unique visitors on a monthly basis than others. The game is about attendance reduced the number of unique visitors in a period of time, not the amount of content, or optimization, or some sections that dragged visit from a search engine like crazy. Of course I do not mean that the amount of content, or optimization, or something else is not important, but only at the end of counting unique visitors usually on a monthly basis. There is no scale of visitors, which ranks sites by the amount of content, quality optimization or something. The only reason why a particular site attractive as the other is the number of unique visitors.