SEO refers to search engine optimization and involves optimizing websites to increase their visibility in search engine results. The document discusses why public agencies should pay attention to SEO, including to protect their online authority and keep up with changing citizen behavior. It provides tips for public agencies on SEO best practices like using relevant keywords, adding external links, and avoiding obscure acronyms or hidden web pages. Newer factors like social media data and links are also becoming more important for search engine rankings. The document encourages public agencies to evaluate if SEO is worth investing in to better serve users searching online.