In "Challenge 10 – Keep Your Gatsby Site Blazing Fast," Hashim Warren discusses strategies to enhance the performance of Gatsby sites, emphasizing the importance of speed for SEO and accessibility. The #100DaysOfGatsby challenge encourages both newcomers and experienced users to deepen their understanding of Gatsby by building projects and following prompts. The article highlights key resources for improving site performance, such as using Lighthouse for performance audits, employing Guess.js for intelligent preloading based on user navigation patterns, and utilizing CDNs like Cloudinary for media assets to reduce build times. Additionally, it suggests experimenting with smaller JavaScript runtimes like Preact for further optimization. Warren also provides avenues for support through the Gatsby community and encourages sharing experiences via social media platforms.