Mediawiki vs SharePoint

MediaWiki is a popular free web-based wiki software application. Developed by the Wikimedia Foundation, it is used to run all of its projects, including Wikipedia, Wiktionary and Wikinews. It is written in the PHP programming language and uses a backend database.
SharePoint's multi-purpose platform allows for managing and provisioning of intranet portals, extranets and websites, document management and file management, collaboration spaces, social networking tools, enterprise search, business intelligence tooling, process/information integration, and third-party developed solutions. SharePoint can also be used as a web application development platform. SharePoint alternatives for small business are: Office 365, Box, G Suite, Zoho. There are also free open-source alternatives to Sharepoint - Alfresco, Nuxeo, Liferay Portal.
Face to face in the news:

2001 - Microsoft unveiles enterprise portal SharePoint Portal Server to strike back at Mediawiki

SharePoint Portal Server

Following the release of free MS Office extension for creating internal collaborative web-sites SharePoint Team Services, Microsoft has uveiled a full-fledged (and paid) enterprise portal SharePoint Portal Server 1.0, that will compete with portal solutions from IBM and Oracle. SharePoint Portal Server enables companies to create internal portals for collaboration and data access from both local and external sources. In particular, the portal includes tools for document management, search and creating sites with the help of Web Parts technology. It uses IIS web-server and Web Storage System (WSS) database that is used also in Microsoft Exchange. Users can access portals via web browser. Unlike SharePoint Team Services the portal provides more advanced tools for document management, version control, workflow management, search, access control and creating websites. SharePoint Portal Server is targeted primarily for medium and large companies and cost - $6,999 for a 25-user license.