(1). When your product or service becomes synonymous with it’s function. (i.e. Kleenex is a brand of tissue, not the tissue itself, and Google is a search engine, yet people use the brand name as the actual action of searching. See, now you get it, and if you don’t and are upset about not getting it, then grab a Kleenex and go Google it, lady).
“You see Ted, your problem is that you have somewhat of a Kleenex issue on your hands. On one hand, everyone knows your product and brand, on the other, nobody can differentiate between the two and your competitors use both in all of their marketing material. Guess that patent idea I gave you 10 years back makes a whole lot of sense now, doesn’t it Ted?”