I created a Post It Wall with SharePoint. I created a custom list with the following fields:

Subject - Drop down list with Project, Idea, Note, Thoughts, Suggestion, etc
Note: - Rich Text - 10 rows
Date Started
Date Completed
Created by and Date
Modified by and Date

Using FrontPage 2003 to set List View Details, then I converted the list to XSLT Dataview. I modified the list using tables and cells to make each note to appear as a post it note. I sorted the list via subject and collapsed the list. The list appears as a collapsed list, but when you expand a subject, each entry in that subject is a yellow post it note.

Here are some screen shots.

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Collapsed View

Expanded View