Level 100 - Involes an introduction of the topic. Good for situations where simply an understanding of the technology is required. Recommended for end/business users.
Level 200 - Normally involves configuration steps. Does not require any development activity or programming skills.
Level 300 - This is the level most recommended for developers who have no prior experience with the technology.
Level 400 - Involves advanced topics. Recommended for developers who have prior experience working with the technology or who want to go one step ahead.
Level 500 - Normally involves complex and advanced topics. Recommended only for developers who have complete understanding of the technology and the .net framework.