Issue tracking systems are complex task managers (todo lists) used by software developers. Issue tracking systems, sometimes also called bug tracker or ticket systems allow one group of users (end users) to create tasks or issues or bug reports, which another group of users (developers) can see, solve and modify.

Developers are able to see what issues are there, who is working on what issue, and what issues have been closed recently. The end users can track the progress of the issue they reported, send feedback or search the system for similar issues and possible solutions. 

With the emergence of bottom-up management the concept of issue trackers can be used for managing tasks among knowledge worker teams, as long as the system is powerful and easy to use like the Mindquarry Collaboration Server's task section.