Believe it or not, the simple TODO.txt ticks a lot of boxes when it comes to collaborative issue management. Check out this list of cool features for the mighty TODO.txt file.

• Full Version History - when used in conjunction with GIT or SVN
• Task Prioritisation - TODO items can be reordered into priority order
• Release Management - TODO items can be put into different releases.
• Centralised Issue Management - when used in conjunction with GIT, SVN, FTP or WebDav
• 100% Collaborative - Many developers can view and edit TODO.txt at once with little risk of conflict.
• Low Cost - there are no licensing fees.
• Easy to install - no web server or desktop client needed. Use with your existing text editor (Notepad++, TextMate, Visual Studio or Vim recommended).
• Easy to Learn - it's as simple as typing text!
• Non Intrusive - use TODO.txt from within your IDE whilst developing.
• Small Footprint - uses almost NO memory or CPU.
• True Mobile Platform - TODO.txt works on 90% of mobile phones.
• Cross Platform - TODO.txt works on any computer platform created after 1960.
  
• Easy Import/Export - Export data to any other bug tracker using RegEx and SQL.
• International Support - when used with a UNICODE compliant editor.

Ok, this is a bit tongue in cheek, but you have to admit, the humble TODO.txt has a lot going for it.

Example

Here's part of the TODO list for Squilbo, a web based database tool I'm working on.

Key
===
* =  This release
> = Bumped to some future release
x = Done or Cancelled 

Feature: Schema Browser
=======================

* show stored procedures
* show functions
* clear and show waiting signal whilst loading new schema view
* show "Please wait" when loading data from server
* drag n drop tablename onto query

> right click table gives option  "Select top 100 records"
> right click on column gives option "Select top 100 distinct values"

x show data types on hover over column name
x show views 
x refresh databases drop down on connect
x show key columns with different icon

So this question is this. I'll obviously have to move to something more sophisticated after release 1 of my little project. But what is the next step up?

Humour aside, can anyone name a bug/issue/task tracking tool that comes close to the criteria listed above, and builds on them? And no, Excel is not an option I'd consider :)