it also really doesn't sound like "if you use MongoDB in your streamingplatform/blog/whatever you need to opensource everything, which seems to be the gripe many a commenter is having.
Maybe. If there's more lines of code in the Mongo part than the other part, is the value "primarily" Mongo? What if I made a file upload/download site? Mongo might constitute the bulk of the value/lines of code/whatever.
Words like "primarily" and "including, without limitation" make lawyers nervous.
That depends on how you think a court would weigh the source of value of your offering; and any factor that makes MongoDB more valuable as a component before considering the license makes it more risky when you consider the license.
Words like "primarily" and "including, without limitation" make lawyers nervous.