We have talked about this useful add-on before. And now this ...
Link to article:
Adblock Plus now sells ads | The Verge
There is a way to turn off the default which is to allow some ads. Open Adblock Plus (this step varies by browser). Click on Filter Preferences. Clear the checkbox for Allow some non-intrusive advertising.
By the way, to be clear - Adblock Plus is not the same as Adblock. Comparison:
Adblock vs. Adblock Plus: Which is Better?