Are you thinking of an Intranet Solution?
Some of the popular features for a medium sized business include:
Pages - for company and departmental access
Blogs - for employee blogs
Calendar - listing of company events and announcements
Document library - a place to search for forms, downloads, policies and procedures
Books - to develop online documentation in structured form
Site Search - for searching pages, posts, and documents
Roles & Groups - must have the ability to create custom user groups and roles
Security - each page/post/document can be restricted to roles, user(s), or group
Nice to have features:
Discussion forum
- Staff directory
Chat
In/Out Board to list employee statuses
Publishing videos