Most people know that AdSense isn't profitable anymore and that the best days of the whole PPC advertising model have already passed them by.
Here's the funny thing though. Everyone I talk to tells me how horrible business is with PPC and how much profits have dwindled, but no one tells me they stopped using it to monetize their site.
If AdSense isn't making you money, why do you continue using it? I've long since ditched PPC for my advertising profits, switching instead to CPA. I couldn't be happier.