In an MVC or MV* model, the controller (in this case, the Blaze rendering engine) is sometimes called the glue. That's because it "glues" together all the view items, such as buttons or textboxes, to the model. Blaze does this reactively, using reactive contexts and reactive computations, vastly simplifying the "gluing" process for you, the developer.
Pretty fancy explanation, eh? Well, you try to come up with a better explanation for what it does. It really does fill in the cracks and keeps the model and the view together. Someone else invented the term, not us; so, let's continue without the Judgy McJudgerson viewpoint, mmmkay?
In this section, we'll go through all the changes that need to happen inside