I can’t speak for “Biotest”…but a basic tenet of marketing is “Demographics”. In other words, if you don’t know who your market is, at best you’re speculating and blowing in the wind…at WORST wasting a lot of money.
This is an exteme example, but i think that it illustrates the point:
“Biotest” would probably waste a lot of money advertising in “Shape” and “Fitness”, even if they brought every other page of advertising. Again…this is an extreme, (and they probably would know that without a lot of research), BUT it DOES help to know roughly just who your target consumer is and what they like. Market research would reveal that the soccor moms of “Fitness” would probably not represent the best place for “Biotest” to spend their marketing dollars.
With that being said, there are other reasons for collecting information on your customers, but certainly demographics for marketing purposes ranks high on the list.