This article is strictly referring to online poker games. It has nothing to do with reading the players. You can read here about some moments in the game when it is likely for others to bluff.
1. When they are still betting after a bad flop
Watch other player. Lets say they already did bet pre-flop and their position was not that good. Now the flop is on the table and it is poor, so you have to think they could be bluffing. So raising the bet, or re-raising it might make them think about it, because they probably stand zero chances with the drawings and they might fold.
2. The odds are with them
For example, when everyone folds. And especially when the pot is quite big, like a drawing missed and maybe even you are thinking of bluffing. Then, you should naturally think that they could also be bluffing. So call or raise, whatever you want, just dont throw away such a big pot.
3. When theres only the two of you.
Its considered the easiest bluff. They will think that if they got that far, they might as well get on with it. But dont be fooled and if you have a good hand go on and play it.
4. When the flop has no more...