A Space Admin can choose which Associated Projects to make visible on their Spaces page, via the Spaces Edit page
For example, if there are 100 projects participating in a Hackathon that is an Activity of a Space, then those 100 projects are "Associated Projects" of that Space, and not visible by default. Let's say that 5 of those projects win the Hackathon. Then via the Spaces Edit page, the Admin could choose to have those 5 projects visible on their Spaces page, while the other 95 projects remain "Associated Projects" that aren't visible.
Edited by Brad Fujimoto