The platform should have features similar to that of jaiku/twitter.
Also for your reference, something on the lines of this microblogging site "http://www.soup.io/".
Outline of some specifics:
*The script should allow people to post images,video links,and messages(micro blog posts).
*Each 'microblogger' would have categories within which he/she could dump stuff(images,links,messages) into, tag management etc.
*Users can subscribe to other users 'feeds'.
*Site would also have an admin area
Look forward to your bids and maybe an sample site or more.
- Thank You