Your country: US
Reward types: Cash and gift cards
Incentives per survey: 0.50 to 3 US$
Cash out: from 5 US$ (5.500 LifePoints)
Number of invites: about 10 surveys in a month
Age to join: from 16 years
Comments: MySurvey and GlobalTestMarket have new names and are now Lifepoints

Your country: US
Reward types: gift cards and cash via prepaid card from VISA
Per survey: 1 to 3 US$
Cash out: from 25 US$ (2,500 points)
Number of invites: about 10 surveys in a month
Age to join: from 13 years
Comments: Prepaid card from VISA are sent by post, but you can also request a virtual gift card

Your country: US
Reward types: Sweepstakes for cash only
Number of invites: regularly due to sofware use plus occasional surveys
Age to join: from 18 years
Prize draws: Monthly $ 10,000 cash for 10 winners, stay active on the panel
Comments: This is a Nielsen special panel (world's major market research institute). You need to install software, which permanently tracks what Web-sites you visit - online surveys may be conducted on internet usage accordingly.

Your country: US
Reward types: Sweepstakes (to win cash & valuable prizes) only
Number of invites: about 7 surveys in a month
Age to join: from 13 years
Prize draws: Every month 16,500 US$ total in the US and many valuable gifts, also 1,000 US$ prize draws for new members