I've been a member of Crowdtap for approximately two months. Since then, I've earned enough to cash out and have already received my Amazon.com gift code as promised.
How Crowdtap works: You sign up and then you answer quick hits and questions to earn points and money. Once your account reflects a $10 balance, then you can cash out for Amazon. 5% of your total will go to the charity that you selected upon sign up. The more thoughtful your answer, the better chance that you have that you will receive a star (worth points) or even be chosen to win the $25 for the discussion you were invited to. I've never won that, but I keep hoping! Being awarded stars not only gives you points, but you also get points toward your quality score. If your quality score drops to zero, then your account will be suspended. Avoiding a zero is easy if you provide thoughtful answers when asked.
The more points you accrue, the higher level you become, which enables you to be invited to more discussions and perhaps even be invited to a product trial. I noticed that the higher my level went, the faster I was able to reach the payment threshold.
Does it take a lot of time? I don't think so. I made sure I checked the box for email notifications, so when there are quick hits and other discussions available for me to do, I get alerted. You also get 10 points for signing in each day and 25 points for daily comments. These points options are easy to take advantage of to build your level fairly quickly.
Want to join? Crowdtap is currently invite-only BETA, so you will need to be invited to get in! I'd love to refer you. What I like most about Crowdtap is being able to give my opinion. Some surveys want you to just check a box and the discussions at Crowdtap really let you tell a company everything that that radio button choice didn't give you the option to say. I also love the Amazon aspect of Crowdtap -- earning toward Amazon is fairly easy. Plus, the charity aspect is cool too.
You can join Crowdtap by using my referral link.
Disclosure: Crowdtap does have a referral program. Joining via my link would benefit me.