Thanks for the response, Pablo.
As long as people understand what they are doing, then I have no problems with it.
I did have problems with how it was phrased and how the information was possibly going to be used (it was unclear - not just personal information but the comparisons between sample sets, or in this case clubs). If the method of collecting the data is clearly stated (i.e. lots of surveys over lots of different social groups) and the data is correctly normalised then that's fine as long as people know how the data is going to be compared, and the same question is asked of each sample group. Stating the "result" of a rival isn't the best way to get people to try to complete the survey/test honestly in my opinion (just my opinion!). It also doesn't breed confidence that the survey that one club gets (e.g. Villa) is the same that another gets (e.g. Blues), and the average of a club with 10 responses is better than a club with say an average of 100 responses.
Anyway, I've rambled on a bit - it is afterall up to the individual to decide.
Sorry to cause a bit of a hoo-haa out of it but I think you would have been better to have a single test link
Have a good weekend.