Topics can be described as more narrow perspectives within an area.
Here's an example: If you create an area called "Relationship" you need to narrow it down at the topic-level. Four topics specifies various relationships such as:
- Our relationship with internal and external influencers
- Our relationship within the user community
- Our relationship with decision makers
- Our relationship with approver/signing authority
As a result, you narrow an area down with topics until it become action-oriented and practical by adding questions.
Best practice is to have as few topics as possible in order to keep the total amount of questions down. However, it's still important that all aspects are identified and covered.