The free OpenCalais service and open API is the fastest way to tag the people places facts and events in your content. It can help you improve your SEO increase your reader engagement create search-engine-friendly topic hubs and streamline content operations saving you time and money. From a user perspective its pretty simple: You hand the Web Service unstructured text (like news articles blog postings your term paper etc.) and it returns semantic metadata in RDF format. Whats happening in the background is a little more complicated. Using natural language processing and machine learning techniques the Calais Web Service examines your text and locates the entities (people places products etc.) facts (John Doe works for Acme Corporation) and events (Jane Doe was appointed as a Board member of Acme Corporation). Calais then processes the entities facts and events extracted from the text and returns them to the caller in RDF format.OpenCalais is free to use in both commercial and non-commercial settings but can only be used on public content (dont run your confidential or competitive company information through it!). It is your responsibility to police the content that you submit so make sure you are comfortable with our Terms of Service (TOS) before you jump in. You can process up to 50000 documents per day (blog posts news stories Web pages etc.) free of charge. There are a number of easy ways to get started.* Calais Tagaroo: If you are on WordPress try the easy-to-install Calais Tagaroo plug-in which automatically tags your content as you type. It can also fetch images from Flickr and videos from Google Video which you can select for inclusion in your post or disregard.* Calais Marmoset: If you want to manipulate your search results appearance in Google and Yahoo! you can try Calais Marmoset which is simple javacode you embed in your site pages. Marmoset will collect the metadata from your page (in the form of RDFa) and hand it over to Google Rich Snippets> and Yahoo! Search Monkey so that you can customize the way your search results appear.* Semantic Proxy: If you want to extract metadata from Web pages using URLs then try our Semantic Proxy service at SemanticProxy.com.* Calais Collection: If you are using the popular open source platform Drupal you can find a complete Calais Collection of modules for easy integration.* OpenPublish: If you are building a new site from the ground up consider usingOpenPublish a free Content Management System based on Drupal. OpenPublish bakes-in OpenCalais from the ground up to semantify your site and automate the creation of related reading widgets topic hubs and more. OpenPublish comes from Phase2 Technology and Thomson Reuters and now comes with the option of fee-based support and hosting from Drupal founder Dries Buytaerts company Acquia.