300,000,000 people take online surveys

I was reading about "PollFish" which is into market research and they send online surveys to worldwide people who get registered with affiliate websites.

Data showed some 300,000,000 internet users take online surveys and get paid for it. Companies/market researchers buy surveys costing $1 each with PollFish which are then sent to respondents. Each survey has 15 questions .

SurveyMonkey has some 30,000,000 members. They also buy and sell online surveys.