Page 159 in the Hold 'em for advanced players:
"In a loose passive game where many people see the flop and then play poorly after that... You should: .... Frequently keep it to a single bet before the flop more than most people think because you gain a lot when bad players make incorrect calls on the flop and beyond, as long as the pot is kept small....

With a hand that is pretty good but not great, if you don't raise and thereby cost yourself a little bit of money at that point, you gain it back plus some because had you made the pot bigger there would be less opportunity for your opponents to make significant mistakes later on."

Not very well worded, and it took me 2 or 3 times of reading it to understand, but it proves Brendan's point exactly.