In BSCW you may create, manage and share objects of different types in one workspace (for sharing see 4.3.3 Invite members).
The symbol in front of the object indicates to which type the object belongs.
More:
Document
Document under version control
Chat message or note
URL
Folder
Contact list
Email message
Search folder
Template folder
Wikis or Wiki
Calendar
Date coordination
Community
Task
Flow Folder