Not everything runs smoothly even in Agile. Sometimes there are blockers which do not allow to continue to work on tasks.
Impediments, in agile terminology, are simply blockers. ScrumDesk supports tracking of impediments on both levels: backlog item level and task level.
Impediment in ScrumDesk is a flag that can be turned on or off. It is possible to turn it directly on a card, or in details. Further details about impediment can be tracked as comments.
In many cases, the blocker is about wait time for somebody outside of the team. Experienced Agile teams prefer to distinguish such blocker type by waiting flag that can direct scrum master to quickly solve communication issues. Similar to the impediment flag, waiting flag is indicated on a card and in side view by small red flag.