Logging options
Tracking

Logs at creation, invocation begin and end.
Timing

Logs after each single activity execution (ie, not after activities defining a group_method_id) its execution time.
Tracing options
Creation tracing

Controls whether activities should contain a stack trace from their creation. It helps finding out where an activity comes from. Those traces are logged and mailed when an activity fails (as part of regular activity failure mails).
Activities Maintenance

Recreate activity tables, preserving existing messages.

Recreate activity tables, throwing away all contained messages.

Controls the visibility of links to cancel or invoke activities from "Activities" tab. These links are too dangerous in production environment and they must not be visible.