Many of you have been discussing the effectiveness of IBA and whether to opt in or opt out.
We have just launched a new feature in the AdSense interface that now shows interest-based targeting type earnings broken out. Previously these were included in contextual earnings. Now if you want to see how much you're earning from IBA, here's how:
1. Under Performance tab, click on the 'Accounts by entire day' drop down
2. Click 'Targeting types' under this drop down
You should see data broken out by contextual, IBA, and placement.
For those of you who aren't opted in, I'd highly recommend reconsidering opting-in and tracking the results.