Reason #1: They're doing interesting things with their marketing strategy and tactics. Being big, they have the resources and capabilities to try new marketing ideas, analyse the results in an objective way and then decide what works and what doesn't. When something new succeeds big, it's big news. When something big isn't successful, that's also big news.
Reason #2: These companies are constantly being covered by the media, so it's easy to find out what they're doing and link to multiple reports about their marketing activities. Also, being public companies, they tell their investors a lot about their marketing, which means readers (and lecturers) can dig deeper to learn even more about what a particular firm is doing.
Reason #3: You know who they are. I always like writing about smaller marketers, because they have a lot at stake when they make a marketing decision, and some may very well grow up to become the Dixons of the future. But to show marketing concepts and theories in action, it's also good to base some case studies and write-ups on businesses that readers know or are customers of.
Of course, I also blog about global marketing firms that are in the public eye, such as Walmart, Nestle, Kraft, Danone, Samsung, Lenovo and more. These, like the Tescos and Asdas of the world, are market leaders and their marketing makes a difference locally and internationally.
