I was reading a random online marketing strategy for a some business. The person who prepared the document also discussed about the competitors of the clients. I saw that the preparer was able to identify that how much the competitors are paying (approximately) for their adsense campaigns. Secondly, it was also mentioned that how many keywords they are targeting and how much clicks they are receiving from these campaigns. I want to know that how can a person analyse the competitors strategies with such intricacy that he can even share the numbers? Thank you.