Best type of blog post for long term traffic?

A study looking at different types of blog post and their effect on long-term traffic showed:

• Topical: articles based on timely events that were in the news gain instant traction, as they are well shared, but receive few long-term visits:
• Promotional: any blog posts directly promoting the business or services attract engagement but don't drive much long-term traffic:  
• Instructional: posts that tell you how to do something, or giving step by step instructions achieve higher visits initially and long term traffic:
• Knowledge: posts that may be educational but without providing instructional advice are the strongest as people tend to search the internet to find out how to do things:

Thanks to the Econsultancy blog post and the study by Steve Masters at Red Rocket Media