The West is the only place where Observers can directly interact with the story. It connects all the seemingly irrelevant or unrelated elements together. I think VB said that it's like a spider web, and all the other stories sit in it like gemstones.

There is a main arc, it's parts are called loops. There the Observers command Peewee who has cybernetics that allow this.

There are also intermissions, they are shorter, and there the focus is on other characters. The first few doesn't really affect the main arc, but later they have more to do with each other.

You could also influence the story there, if you'd like to, assuming that haven't hundred years passed, and this branch haven't ended by the time you read this. Time is fake anyways.

~The Watcher of Threads