There are thousands of people using these websites because they're not really a waste of time.
They're great for Driving loads of traffic towards websites and YouTube videos.
Most of these websites don't give you anonymous traffic though. So Google Adsense will ban your account quickly, or any advertiseing company.
I found
http://anonwebhits.com/ which is the only one I know off that gives anonymous traffic for free.
I believe
http://customhits.net/ also gives anonymous traffic, but to premium members only.
These websites can come in pretty handy though. I tried using one of these services for submitting my pages to stumbleupon and I got amazing results. I had thousands of visitors coming in from stumbleupon.