1) Traders, including the grannies sitting in China stock brokage houses.
2) Hedging fund: people who have short positions, options…all these are closely related to the general market, and can have a wider swing than common stocks.
3) Mutual fund: because they have a large portifolio, they are exposed to the general market condition (weak, strong, swing etc.)
4) Economist and reporters: it’s economist job to predict the economy; and it’s reporters’ job to report the market.
5) Jim Cramer of Mad Money, Fast Money crews, both from CNBC; No. 1 Caijing, the popular financial TV channel in Shanghai; many other financial channels all over the world…
I think people pay attention to the market mainly for two reasons: 1) It’s their job; 2) It’s where they make (or lose) money.
On the other hand, who cares Mr. Market the least, or put the other way, who usually takes advantage of the weak or wild market condition to make money?
You guessed right: Mr. Buffett and other value minded investors. Note I did not use value investor because that term is mis-used in many occassions.