I get e-mails ever once in a while asking if I'd like to write for a medium blog. I always ask how much they're paying and never get a reply.

I'm fine for writing in a spot I can get exposure, but you better pay me. Medium does pay a subset of their writers. I know when they started The Nib, they paid political cartoonists like Matt Bors. So they paid a small group to get others to contribute. They're pretty much the new Huffington Post.

How exactly does that happen btw? What are all the discovery mechanisms? Once the network is saturated like the Web, what does it do to allow new blogs to be discovered, besides just a "new on X topic" section and stuff people can do anyway to share urls?

Thst only explains why they would syndicate to Medium, not host there.