This document discusses some of the key challenges of mobile search engine optimization (SEO). It notes that more searches are now performed on mobile than desktop, and users spend most of their time in apps rather than browsers on mobile. Some challenges for mobile SEO include properly configuring robots.txt files to allow crawling of CSS and JS files, ensuring content within apps matches content on websites, and determining whether to build apps or focus on responsive websites. Experts comment that app links in search results perform well but responsive websites can also be effective. Overall, the document outlines technical and strategic challenges for optimizing content and apps for mobile search.