Wikipedia
FogBugz is an integrated web-based project management system featuring bug/ issue tracking, discussion forums, wikis, customer relationship management, and evidence based scheduling developed by Fog Creek Software.
The feature tracker allows users to manage, filter, sort and navigate a tree-structure of tasks, that contain information, tags and attached files related to a particular issue. Discussion forums and wikis may be created around any topic and posts/pages may be added into the same. Users may integrate their email accounts into the system to send/receive email and create issues regarding the same.
Prediction of future tasks and completion estimation of future milestones are based upon past records of user performance. Users must manually input an estimated duration for every task, and state the task they are currently working on which builds a daily work log (timesheet) that may be reviewed later.