Simplicity and usefulness is the essence of a good product

Few days back, a friend suggested an offline wiki to take notes. I decided to check it out and found it really cool. The best thing about it is its simplicity; yet it is very useful. That according to me is the essence of any good product.
Tiddlywiki is a very powerful concept. You can work offline in an html file and save it. It uses html, css and javascript and runs on any browser. Some important features that is provided by it are,

• Formatting and indenting
• Various interface options
• Backup and autosave
• Embedded images
• RSS feeds
• Keyboard shortcuts.
• Search Facility
  

To use it, all you have to do is save the source of Tiddlywiki and start using it. It saves the file when you save the note. All it does is allows you to re-write the file. Your notes are saved under headings provided by you. These can be browsed from the list provided at right side of the page. The best part is this small file allows you to search through the content.
If you have little html or javascript knowledge, you can play around with the code and make the most of this concept. I must admit ... some really good thinking here by Jeremy Ruston, who originally created this wiki.
The success of an idea, or for that matter, a product, depends on its usefulness and the ease/simplicity with which it can be put into shape. That's what matters.. other factors can follow.