I put forced image ads on my site, and my daily income was $10-15. I switched to text or image, and it went to $20-30.
I'm not sure how much they worth, but one thing is for granted. There are three types of surfers 1.- those who never click on textual advertising 2.- those who never click on image advertising 3.- those who use tricks to avoid any type of advertising displayed. In addition to AdSense publishers who avoid click on others' adSense ads