An Electronic Noticeboard (E-N) system is needed to facilitate communication between people. It will allow notices and messages to be posted by users to enable discussions on topics to take place.

The Electronic Noticeboard contains two main areas, the noticeboard and discussion groups. The noticeboard contains a list of notices that are added by registered users of the system. Each notice has an expiry date, (the date after which the notice is removed from the noticeboard); date posted, a notice subject and notice text.

Discussion groups are organised around broad areas of interest. Within a discussion group a user starts a new discussion topic by posting an initial message. Other users can respond to this message by posting follow-up messages, which in turn generate further follow-up messages.

The system will be available over the internet, and message can be read by any web-user. To post messages the user must be registered with the E-N system.

A system administrator is able to start the system, add new discussion groups and maintain the messages by removing unwanted messages from the notice board and discussion groups.

I need to find....
At least three (3) Use Cases from the problem set and using Visio modelling tool create three Use Case Diagrams.

This seems like a homework question to me. How about you give it a shot and show us what you think are some use cases for it and we can elaborate.