because only a very limited of operations can not be logged, normal inserts and updates and deletes will be logged, indexes will always be logged.
You could also have force_logging set at the database level
Nologging noe of the most misunderstood concepts I believe
I have a 9.2.0.6 runiing in archive mode, and tables are on no logging in a schema. When i look i still get huge archive streams fro that schema. How is this posible