The development of large language models (LLMs) has revolutionized how we search the internet for information. AI search engines are integrated with LLMs, enabling them to accurately identify user intent and generate customized responses. OpenAI Search is a widely used AI search engine that combines GPT-4 models with traditional ranking techniques, providing contextual understanding and personalized responses. Google's AI search engine uses real-time surfing of the web and machine learning algorithms like RankNet and LambdaRank, offering improved reasoning and logic capabilities. Bing Search integrates with Microsoft products, supporting visual search and video previews, while also providing a personalized shopping experience. Perplexity AI provides transparent source citations and dynamic LLM model selection for research purposes. Arc Search is an AI-powered mobile browser that prioritizes user data privacy, generating quick responses to queries. RAG (Retrieval-Augmented Generation) is a technique where LLM models are combined with retrieval techniques to generate context-relevant responses.