The real WTF (that you, me, and the OP probably agree on) is the California initiative process, which forces/allows citizens to act as legislators.
But to your point, the first substantive link off the official Prop. 30 summary page (http://voterguide.sos.ca.gov/propositions/30/analysis.htm) makes clear in several places that the increases will take effect starting Jan. 1, 2012. ("Because the rate increase would apply as of January 1, 2012, affected taxpayers likely would have to make larger payments in the coming months to account for the full-year effect of the rate increase.")
If the OP was worried about taxes, he should feel lucky that 38 failed ;-).
"The real WTF (that you, me, and the OP probably agree on) is the California initiative process, which forces/allows citizens to act as legislators."
I definitely agree with this (-:
You're right, in that a reasonably informed voter should have known the nature of the proposition. Unfortunately, due to the broken initiative process, those weighing the options tend not to be sufficiently informed. In my opinion (though not that of the US Supreme Court, see Calder v Bull), such ex-post-facto tax laws should be as prohibited as similar laws are in criminal circumstances.
We're continuing to digress, but I have to imagine that the framers of the (generally successful) US constitution must be having a laugh at the expense of the framers of the (less successful) California constitution regarding the initiative process.
But to your point, the first substantive link off the official Prop. 30 summary page (http://voterguide.sos.ca.gov/propositions/30/analysis.htm) makes clear in several places that the increases will take effect starting Jan. 1, 2012. ("Because the rate increase would apply as of January 1, 2012, affected taxpayers likely would have to make larger payments in the coming months to account for the full-year effect of the rate increase.")
If the OP was worried about taxes, he should feel lucky that 38 failed ;-).