Gatsby blogs can handle comments through client-side services, Git-based solutions, or custom setups, each with its pros and cons. Client-side services like Disqus offer simplicity but lack integration with the site's output, potentially affecting SEO visibility. Alternatively, integrating comments into Git using Staticman allows for complete control without external dependencies; Staticman creates pull requests for new comments and supports spam filtering, offering a free and reliable solution. While custom solutions using serverless frameworks or Netlify provide flexibility, they often require significant effort and technical expertise, making them less practical. Staticman is highlighted as the most balanced option, offering control and independence while being open-source and free, ensuring that comments remain intact even if the service is discontinued.