When you compete on the Internet, you can have competitors that you never knew existed. It is essential that you not only learn the identity of your primary competitors, but also understand what they are doing on the web.
Utilizing tools such as Spyfu and Majestic SEO, I am able to understand the techniques each competitor uses in SEM and SEO. How they build their links, the quality of the links, and even who they get links from. We can also determine the value they place on given keywords and how their Adwords ads have changed.
In effect, we learn from their mistakes, and successes.