I have noticed that when I switched my Ad from a banner to a text Ad, my CPM went to $0.00. So I switched it back it went to $ 1.93. SO I am getting a little tiny bit of money. Anyone know why that is?
CPM is calculated on how many clicks you get, not impressions. Perhaps you are getting a higher CTR with text ads.
Actually, AdSense ads can pay both clicks or impressions. Image ads tend to be CPM while text ads tend to be CPC. My guess is that your CTR is really low (like 0), and that's why you don't get any money for text only ads. When you switch to image ads, CPM based ads start showing and you get some revenue.
Image ads have higher bids because their is ony one advertiser for that space...text ads there is more then one advertiser.