1. A method for selecting website content, the method comprising: obtaining a multiplicity of anonymous first website visitor passive parameters from a first website for a multiplicity of first website visitors visiting the first website, wherein the anonymous first website visitor passive parameters are commonly available whenever a website is visited; obtaining corresponding first website visitor active parameters of the first website visitors from the first website, wherein the first website visitor active parameters are correlatable to a value of website content presentable to future website visitors; generating anonymous statistical mappings between the first website visitor passive parameters of the first website visitors and the corresponding first website visitor active parameters of the first website visitors, wherein the statistical mappings do not rely on any data identifying an individual website visitor; providing the statistical mappings to at least one of website operators, website publishers, search engine operators and Internet advertisers; using the statistical mappings to establish an expected value of future website content provided to the future website visitors, based on future website visitor passive parameters of each of the future website visitors; and providing future website content to the future website visitors based on the expected value of the future website content.