Fill in the blank: In the late 90s, Larry Page and Sergey Brin were working on their own search engine, and at that time they were the first ______.

Larry Page and Sergey Brin's groundbreaking contribution with their search engine, which later became Google, was the innovative use of links as a signal of authority and trust. This concept, known as PageRank, revolutionized search by evaluating the quality and relevance of a page based on the number and quality of backlinks pointing to it. This was a significant departure from earlier search engines that primarily relied on keyword density or directory submissions. Microformats were developed much later to add semantic meaning to web content, not a core innovation of early search engines. Adding advertising banners on SERPs, while a key part of Google's business model, was not their initial technical innovation in search ranking. The HTTPS protocol is related to web security and encryption, not directly to how search engines initially ranked content.