Semrush is a comprehensive digital marketing suite combining traditional SEO tools (keyword research, backlink analysis, site audits) with newer AI visibility tracking across ChatGPT, Perplexity, and Gemini. Used by 10M+ marketers and 35% of Fortune 500 companies, it offers 8 toolkits covering SEO, content, PPC, social media, local search, and AI search optimization -- though its AI features lag behind specialized GEO platforms.