In case anyone is uncertain, my initial take was that this could be a data-gathering exercise but I'm pretty confident it isn't - based on the background of the firm and what's said on the sign up page:
Here's what the sign-up page says:
By going to the next page, please note that:
* We will send you an email with an activation link which you will need to enter in order to active your free PredictWorldCup.com account. You will not be able to submit your prediction without activating your account.
* You give us permission to send you emails related to your PredictWorldCup.com account and your predictions.
The personal information you submit on PredictWorldCup.com will not be used for any other purposes than activities related to PredictWorldCup.com and will not be shared with or sold to third parties. PredictWorldCup.com retains the right to use the information collected on an aggregated level while maintaining your anonymity.
Bob