bb/100
Big blinds won per hundred hands: the way to compare results across stakes and sample sizes. At NL100 one big blind is a dollar.
bb/100 is how many big blinds you win per hundred hands. Dollars will not do: a hundred dollars an hour at NL100 and at NL1000 are different results. Blinds per hundred hands are the same at any stake and any pace, so win rate is always quoted in them. At NL100 a blind is a dollar, and the figure equals dollars per hundred.
What counts as good: the accepted view is that at NL100 fast poker a regular holds two to five bb/100 after rake, and that is already a strong result. One 300-hand session gives a figure with an error of tens of blinds, and says nothing; a win rate worth trusting needs tens of thousands of hands.
An example from session 9
Over nine sessions and 2,742 hands my win rate is 8.96 bb/100, and the room's commission is 8.4 bb/100: what I pay almost equals what I win. Before rake the series brought $476.65, after it $245.62. The 8.96 guarantees nothing: over 2,742 hands the spread is so wide that the true win rate could be zero or twice as much.
The same in business
bb/100 is the unit in which results of different scale become comparable: margin rather than revenue; revenue per employee rather than revenue. And the second half of the lesson matters more than the first: any such figure has an error, and over a short stretch the error is bigger than the figure. A quarter is three hundred hands.
The whole hand is in session 9: “If you get to choose, be the marketplace, not one of its users”.
The other terms are in the glossary.