How far can you stretch a brand without diluting the power of the core?

The answer it seems is “it depends”. The stronger and more defined the brand, the more it stands for something specific, the less adaptable it is, and the converse is also true, the less defined a brand, the more able it is to be stretched, but on the other hand, why would you bother?

 Should Coke launch a lemon variety?

Should Harley Davidson build a scooter?

Should Louis Vuiton sell a 69.99 suitcase?

 Extending a brand is a sport of choice amongst marketers, the arguments are strong, mostly around leveraging the brand building investment that has already gone in, but it fails to understand that consumers build brands, not marketers.