Here is an example of the survey invite:-
"... We'd like to invite you to take part in today’s study about telecommunications.
If you qualify and complete this survey you'll collect 20 Fly Buys Points! These points will show up on your Fly Buys account approximately 14 days after the survey close date.
It should take approximately 15 minutes to complete this survey. We hope you find it interesting!
So that your views can be included we need you to finish the survey by the 6th of March 2012. This survey may close earlier if the target number is reached.
Your answers are completely confidential. Your views will be grouped with those of others so that individual people and their answers cannot be identified.
To start, just click on the link below. If you need to, you can stop the survey at any time on the way through and return to the same point at a later date."
It makes one wonder...