What are the Interwoven Behavioral Tracking and Targeting Functionalities available?

System

Hi All,
I have a requirement to do targeting based on the last 5 user clickstreams. For Eg. user should be displayed a promotion based on the last 5 categories he has navigated previosly. It can be either session based or can be persisted for the user.
I have three related questions:
1. How does the clickstream works in Targeting Rules
2. If I need to build a custom BOM, how can i track the users behavior?
3. What is the OOB support for Behavioral Tracking and Targeting?

Regards,
Deepali