You haven't read the FAQ/About page probably.

Programmers - Stack Exchange is for expert programmers who are interested in subjective discussions on software development.

This can include topics such as:

• Software engineering
• Developer testing
• Developer tools and techniques
• Practical algorithms and data structures
• Design patterns
• Architecture
• Development methodologies
• Quality assurance
• Software law
• Code golf & programming puzzles
• Freelancing and business concerns

I think that most of this topics are not allowed on SO because they tend to reflect the personal opinions of the answer authors. SO is more for practical examples and objective facts. (Correct me if I'm wrong)