DuckDuckGo Zero-click Info includes topic summaries, categories, disambiguation, official sites, !bang redirects, definitions and more. You can use this API for many things, e.g. define people, places, things, words and concepts; provides direct links to other services (via !bang syntax); list related topics; and gives official sites when available.
Generate Word Clouds from blocks of text. Multi color and different sizes illustrate the frequency, and the "vibe" of the bigger text. Try it with blog posts, article text, speeches, tweet histories, emails, or any other written word.