I am sure people enjoy reading your hubs, EF DOOM, but the sad fact is that we are in the midst of a recession. People don't really want to buy anything right now. People are coming, reading your work, and being enriched personally, but times are a little rough right now, and so they don't even touch the ads for fear that in doing so, they have racked up a charge on their credit card without meaning to.
Surely money is not your motivation? If you give into this temptation, you may find yourself writing to the cash (I mean this as a variation of "teaching to the test"). Then the quality of your writing can then only decrease, and then traffic will go down, and so on and so forth.