Do you find that clicks come from repeat visitors or first timers? In my experience they seem to be coming from people new to my site.

That's pretty typical, though it could depend on a variety of factors. Repeat visitors will probably develop ad blindness and not pay attention to the ads. They're there for your content. New visitors are looking for something and if you don't have it they may click on an add that looks like it does have what they want.

I'd have to agree with the above poster, new visitors are more prone to click ads then repeat visitors. However, depending on the subject of your site even new visitors might never click ads, usually this is for sites based on AdSense, SEO, etc.

in my Point Of view The Visitor Who is Nt Known to Adsense Will Definetly Click On Adds

Thats My Thinking