To avoid the scatology, I'd start with the efficient market hypothesis, which isn't perfectly true, but is pretty close to being true.<p>It's hard to predict the stock market. If there is a lot of hating on a stock, the value is probably low to begin with, which means the stock has room to go up.
If I remember correctly, Jim Cramer's suggestion for how to use analyst recommendations is: don't buy a stock that is recommended by four or more analysts, and if you own it and a fourth analyst starts covering it, sell. It may not be going down, but its best days are behind it.