Why do some pundits attempt to make a search engine out of every successful website? Like "search engine" is the highest form of a website in an unofficial hier

Why do some pundits attempt to make a search engine out of every successful website? Like "search engine" is the highest form of a website in an unofficial hierarchy? Something like: 1. static website 2. blog 3. social site 4. search engine "4" being the highest? Is my blog a search engine because of the WordPress search function in it? Will HN become a search engine?