The Natural Language Understanding API uses natural language processing to analyze semantic features of any text. It provides plain text, HTML, or a public URL, and Natural Language Understanding returns results for the features you specify. The service cleans HTML before analysis by default, which removes most advertisements and other unwanted content. Analyze various features of text content at scale. The service cleans HTML content before analysis by default, so the results can ignore most advertisements and other unwanted content. IBM Watson can understand all forms of data, interact naturally with people, and learn and reason, at scale.