Most reviewed paid survey sites effectively promise not to share personally identifiable information or not to share it without your consent. It's an industry standard by which legitimate marketing research firms are bound. But many membership sites reviewed don't make either promise or do so only in a limited or wishy-washy way. Unauthorized go-betweens don't have to honor marketing research privacy standards.

The only way to make this work would to be a serious survey junkie who can dedicate hours to the work, which defeats the purpose of a side hustle entirely. What’s worse is the idea that you can’t adequately plan your time—a survey might take twice as long as it says or five times as long. That kind of unpredictability means this isn’t a side hustle you can rely on.

Send Earnings may have to be satisfied with the twentieth and final spot in our table, but that’s still an achievement to be proud of in such a competitive market. There’s a good selection of surveys to choose from, which I always welcome, and you can grab your money and run once you hit the thirty dollar threshold. There are lots of other money earning options as well, but watch out for the ‘play games’ pitfall as it could end up costing you more than you actually earn.
MyPoints. This site offered 75 survey opportunities, the most of any site we tested. But it also had the lowest success rate, 9.33%, and a low average hourly pay rate. Plus, the reasons for survey disqualifications often were unclear. On one occasion, we were disqualified after being asked to write the word “Purple.” (Yes, we spelled it correctly.) See our full MyPoints review.
There’s lots of additional ways to boost your income on Vindale, including rewards for opening adverts sent to your email account, or small payments for watching advertising videos online. The site pays out in plain and simple cash, and doesn’t mess around with rewards or gift cards, which many people familiar with the survey landscape find a welcome relief. However, as with OnePoll, you’ll have to earn $50 before you can remove you money from the site, which may not be as tempting as some companies where the threshold is much lower.
Although it might seemed biased to put forth this assertion, the proof is truly in the pudding. Whereas virtually every other way you can earn money online will require some level of skill, more time or the like, paid online surveys consistently offer consumers an opportunity for completely autonomous and consistent participation. This means that there are no contracts, fillers or complexities to navigate, just simple, unadulterated activities that put extra cash in your pockets. 
While surveys vary widely in how they are conducted and used, there are a number of components that are common across nearly all surveys. Many of these common features have been studied in extensive detail by survey methodologists, psychologists, statisticians, and many other fields of research. The general process of survey research is outlined in the figure below.