The document discusses several popular WordPress plugins: - SEO Smart Links allows automatic linking within posts and categories for SEO purposes. - Google XML Sitemaps is easy to use and great for SEO by generating an XML sitemap. - Yet Another Related Posts Plugin improves both SEO and the user experience by showing related content. - Redirection is useful for tracking clicks and changing link destinations. - W3 Total Cache and WP Super Cache both improve site performance through caching but W3 Total Cache has more options. - Google Analytics provides analytics tracking and is easy to use with regular updates. - Tweeted allows embedding tweets from Twitter. The plugin authors