c.im is one of the many independent Mastodon servers you can use to participate in the fediverse.
C.IM is a general, mainly English-speaking Mastodon instance.

Server stats:

3K
active users

Yohan Yukiya Sese Cuneta 사요한🦣

@Tekk@allthingstech.social @robotmonkeys@hachyderm.io @kissane

Simplest answer: Only posts your instance have seen.

The question is, what are the methods your instance is using for its federation?

For example, there are relays out there which push posts to instances subscribed to it.

There are also setups wherein an instance fails to receive posts from another instance because they have a configuration that is preventing them from fully federating (even though both admins claim they haven't silenced or blocked each other).

I am personally not aware of any software with a built-in code that searches the "entire" fediverse network. I think that would be very taxing. It's like being a search engine at that point.