Quote Originally Posted by Valda View Post
Are they interchangeable?

Есть там много людей
или
Есть там многие люди

etc etc...
The explanation I was given many years ago is that многие люди more clearly emphasizes that the crowd of people is made up of individuals (thus the example already given that perhaps some of them like ice cream and some of them don't), while много людей is more about "how many square meters of floor-space do they occupy" (it considers the people as a monolithic mass).