Forum Moderators: phranque
1-st category is numerous, but it tends to shrink as people get more experience (over 50% worldwide at the moment IMHO, but don't be surprised if it comes down to like 10% in less that a couple of years)
2-nd one is negligible and will NEVER bring in a single click-through
You'd be surprised to see how much of the headache resides on your own machine. Try that Ad-Aware program. They even have a free version that you can download.