All of a sudden I got almost 5k unique yesterday... out of no where! Now I'm getting around 5 cent clicks. I was getting lots more when I had little traffic with more clicks. I'm not sure where this sudden traffic boost came from, but I checked on my hosting panel and it said around 4,610 uniques... I might put Google Analytics on my domain to see.
yepp.. You better keep track of your visitors. If they are coming from any PTS campaign, it may cause problem.