I've seen a couple of bloggers participating in Crowdtap. Here's a description from the about us page of their website:
"Shift marketing to a fully collaborative and participatory process between brands and consumers."
"Crowdtap is the on-demand network for participation. Our self-service platform enables marketers to easily tap insightful and influential crowds of people to involve consumers at all points of the marketing lifecycle."
So far I find it very interesting and fun to participate in. They have "quick hits" or small polls for you to take and it takes little to no time to level up and gain points. You can also choose an organization to help raise/donate money too :)
If you want to help me out with one of the task, just visit Business on Main and click the "Thumbs Up" icon at the top of the page. It will help raise money for the American Red Cross!