Update Dez 10th 2014: Nothing changed here, good service, just use it!
Just like Bitcoin Mining, it is only useful if you don't have to pay for your electricity or you will end up simply paying money.
It only uses your CPU whenever there is work to do and pays you accordingly. It is less predictable than Bitcoin which you just turn on and off. Also using your CPU and not your graphics card can of course actually disturb your normal Desktop usage.
- install it and forget it - program is extremely stable and never shows up
- can be told when to be active - f.e. during night time
- no minimum cashout - you can even transfer tiny cent amounts straight to your PayPal.
- does not pay a lot
- my notebook i7-CPU earns around 5 cents a day, sometimes 1, sometimes 14+. Desktop CPUs might do much better.
- slows your computer down during calculations (obvious). Also uses a lot of RAM.
- you can choose how many cores to use and disable it at any time though.
- no referral system
cashout minimum: None
Amount: Depends on your CPU and location
Here you can see my earnings. Lately my laptop wasn't used so much.
Referral System: None
They actually provide an excellent tutorial on their page. You simply install their software, sign up for an account, enter your username into the software and then forget about it. I have nothing to add, except for
"You might have to reboot if the program simply won't install your CPU agents."