A Knowledge Center is a specific community template to support intensive loads of documents and link sharing by enabling formal tagging that leverages the SharePoint Metadata Service (Term Sets).
Hashtags and tags are great way to structure information. They are fast and flexible. But for some matters, they are not enough in the corporate context. Sometimes shared information needs to be recorded in a more structured way.
Knowledge Centers are a solution to encourage knowledge capturing without compromising the social approach that ensures information is shared in a fresh, simple and engaging way.
Formal tagging can be mandatory or not. In both cases it dramatically facilitates later retrieval of information. Its ShareBox is exclusively focused on sharing and therefore all other options (i.e. polls, praises, etc) have been removed.
Finally Knowledge Centers captures all the information shared in external links, bring the metadata to your corporate database and store it in specific sections (documents, videos, links, etc) that are easy to filter and connected to social conversations.