Select a representative sample: Selecting a representative sample from your sampling frame is also important for collecting valid and reliable data about the population of interest. For example, if you are sampling from a large database of customer email addresses and only wanted one response per household, you might want to cross-check each email address against mailing addresses and remove duplicates to avoid some households having a greater probability of selection. Then you would likely draw a random sample from the remaining list of email addresses.
The only problem with rewarding consumers for taking online surveys is that it gives them the incentive to cheat. The more surveys you fill out, the more points you get. So people get creative: They randomly answer survey questions as quickly as possible, establish multiple e-mail addresses to answer the same survey five or six times, or lie about their demographic (a white male says he's a black female, for example) to participate in surveys for which they otherwise wouldn't qualify [source: Frost & Sullivan].
Companies, brands, and organizations from around the globe are constantly seeking the opinions of people just like you to help shape the products they develop and how they market them. They count on paid online surveys to provide them with reliable information. If you spend time online and enjoy giving your opinion, paid surveys are a great way to earn a little extra cash while helping these companies.