it would mostly growth-related data-- you will get how the company has grown over the quarter in terms of users and revenue, what new marketing strategies they have undertaken, new products or features they have released, complaints current users are giving to them, and their overall strengths and weaknesses, as observed objectively by me. The point is to allow you "to keep an eye on your competitors" because most startups don't have the time to do so.

users + revenue is private for a lot of businesses.

For the rest, they all belong to the category of "social monitoring". That's the name given to this. It's a crowded market.