Some survey websites that offers to pay you for taking part in surveys. Often it works as described below:
How it works
After registering an account you have to fill out a profile. This includes things as questions about: Your age, income, hobbies, likes, dislikes, occupation, family, traveling, technology and more. As soon as a survey that fits your profile is available you are sent a link via email.
Screening questions:
Each survey begins with a few screening questions. Most of the time this includes questions about your age, income and occupation.
Survey main part:
Questions in the main part of the surveys can be anywhere between short and easy to long and difficult. The common types of questions are: multiple choice (choose 1 answer), muliple choice (choose a given number of answers), list of different statements to grade on a scale from 0 to 10 (these lists can be very long).
Survey duration:
The time needed to fill out a survey ranges from 5 minutes to 40 minutes.
Survey abbortion:
It can happen at any time during the survey that the system throws you out with a message saying "Sorry, we you are not part of the target group" or "We have enough participants of your target group at this time", if this happens you wont get any money.
Money:
The money you can earn for an individual survey ranges from a few cent to 5 dollar.
Why it doesn't really work:
I have filled in a big number of surveys up till now, and about 95 percent threw me out before I finished. I have been a member for almost a year now. My earnings so far are: 11 Euro. Not nearly enough for anybodies valuable time in my opinion.