I've never thought about a definition of a "core product" before, but it seems to me that it would be something that the company takes seriously, dedicates a lo

I've never thought about a definition of a "core product" before, but it seems to me that it would be something that the company takes seriously, dedicates a lot of time on, and consciously depends on for user retention and growth. I don't think Reader fit any of those descriptions, and the placement alongside actual core products was an advertisement - a hope that it might become something more, but it never did.