Or go beyond monetizing eyeballs. Turn it into a live chat service, so visitors to your website can instantly communicate with you. Or do what Chatterous did and let people create custom IM group chats. Maybe they did these things and I didn't notice, but anything seems better than 'Let's put a toolbar at the bottom of other peoples' sites!'
Depends. It's easy to make a comfortable amount of money even without intent, but the problem comes when you have massive outgoings (office, staff, etc), and tons of investment, where making a good amount of revenue isn't good enough.