For 30 years, the World Wide Web has run on a surprisingly profound social contract: Most sites are free for search engines to access, but if you use their content, you give credit by linking to the source.For 30 years, the World Wide Web has run on a surprisingly profound social contract: Most sites are free for search engines to access, but if you use their content, you give credit by linking to the source.Internet[#item_full_content]