Last year, I started a giant authority site project. The combined total of keyword searches for the 5 main keywords is 745,000 searches with the biggest one getting 245,000 searches per month. Did I think I would get that much traffic, passively all free traffic from Google when I started the project?
No. I expected more. As I noticed with all of my authority site projects, the traffic from long-tail keywords far outweighs the traffic from the main keywords. However, ranking for the main keywords (the most competitive, and most searches) maximizes the traffic I receive from long-tail searches.