Semantic MediaWiki is a type of software that lets you input information into a webpage to help people better understand the information. It works by using special tags to describe what kind of information is being stored in the page. For example, you can assign tags to say if something is a person, a place, an event, or a number. When someone looks up a page that uses Semantic MediaWiki, they can easily read the information and know what the tags mean. It's like giving the page a helpful description.