This is a positive feedback loop. For feedback, "positive" means that feedback is in the direction of error and tends to quickly exacerbate things. "Negative feedback" is against the direction of error and tends to stabilize the behavior of the system.

Simplified: positive feedback loops increase things (plus); negative feedback loops decrease things (minus). Negative feedback can be good because it can reduce bad things, whereas positive feedback can be bad because it can increase bad things. But you can also reduce bad things, or increase good things.

No, that's not quite correct. Positive feedback can either increase or decrease the variable under control. As an example, consider an inverted pendulum. A small swing to the side of upright causes the weight of the pendulum to drag it further to that side of upright. This occurs in both directions of the stable point and is always positive feedback, regardless of the direction.