I am aware of only two fields where the renormalization (sub)group ideas can be systematically and unambiguously applied: particle physics and equilibrium critical behaviour. 1.- Are there any others? 2.- What are these ideas used for in fluid mechanics? 3.- When cosmologists speak about 'electroweak phase transition' what do they really mean? Is it just the fact that Higg's field vacuum expectation value changed to a non null value and its symmetry was spontaneously broken? I am not quite sure where I should be posting this.