I just had a random, yet somewhat interesting idea. You can create google spreadsheet forms that allow you or anyone to post information to a spreadsheet. What this means is that you could create a google spreadsheet, create a simple form which has fields like “note” and “categories”. You then publish that form and bookmark it. Perhaps even shorten it via a url shortener or something. Then, whenever you have an idea you want to capture, just type in that URL and fill out the form. You now would have a mini-database of ideas and notes to use however you like! And you didnt have to download some application, or log into some closed service. Its just in a spreadsheet for you to manage. Plus, you can now customize the look of the form to something pleasant to use.

references:
http://docs.google.com
http://www.mattsilverman.com/2008/10/introduction-to-google-forms.html
http://googlesystem.blogspot.com/2009/04/themes-for-google-docs-forms.html