John Battelles Searchblog Home Archives News Feed Thoughts on the intersection of search, media, technology, and more. Instead of using the site as the discrete unit of discovery, it used the page - a specific unit of content. Its core algorithm, after all, was called PageRank - yes, named after co-founder Larry Page, but the entendre stuck because it was apt). Thats because that search bar only searches whats on your page, not all of Tumblr itself.