Here are a few reasons why you should track AdWords competitors over time. For starters, when you select a "time segment" you have to use view the data in Excel. Sorry Apple users, I love Macs but Numbers isn't up to the task. You need pivot tables. Excel for Mac does do the job.
When you view data in Excel the way I show you, you see that you have many more competitors than you thought as viewing auction insights in the browser only tells a small part of the story.
Have a client that loves to randomly Google her keywords who then sends you a screen shot asking "WHERE IS MY AD?!" This is a great tool to have in your back pocket because it shows impression share or coverage over time. Very useful for "those" clients who think what happens to them on their computer is what the rest of the word is seeing.
Last year, some of a clients keywords had CPCs that were up well over 300% year over year. When I broke out auction insights, I saw that a competitor had really ramped up their program and achieved nearly similar impression share. Their aggressive play in the market made our clicks more costly.
Here's a cheat sheet and 15 minute tutorial that shows you how to view auction insights over time.
