To begin with, the Internet is a connection between computers and does not gather data about the human beings who happen to be at those computers. Basic counts like the number of times a web page is viewed is not sufficient if you can't build a demographic of the viewers. Many computers, like those in schools and libraries, are used by a large number of people. And a return visit, while an important piece of information, still doesn't relate to the demographics that are vital to marketing like age, sex, income, interests, etc. As in other arenas, companies use various tactics to get personal data and demographic information out of consumers.
Contests are a common such scheme both online and off.
The purpose of this protocol is to facilitate the exchange of personal data for goods and services. The authors of the protocol feel that it will give Internet users better control over what personal data they release to web site owners and advertisers. It could also make the practice of exchanging personal data for access to information more widespread.