Personal information may be requested when a user registers to become a member. During the registration, the user is asked to provide his/her name, email address, specific keywords, location etc. These information are collected to make user specific searchers and evidently, to provide better services to the users. Similarly, if somebody subscribes to the websites or, make a comment for a query relating to a post; then the part of the information collecting is that what is voluntarily provided by the user.
But, the website maintains that the information shared should not infringe the Right to Privacy of the individual therefore, information which is found to be sensitive in normal diligence are not shared.