I have to say i have a weak spot for the American 90's indie scene.
It was responsible for the great Elliott Smith, Pavement, Sunny Day Real-estate, Modest Mouse, Neutral Milk Hotel, Magnetic fields.
I see what you mean. That's an interesting detail about history. I've heard an explanation that "indie" was seen as a British phenomenon, while grunge was an American equivalent to it. I'd think they both had something in common with and there were also exceptions; Dambuilders f.e. were from States and Hawaii. But they still had the soft pop sound in it as most of the bands labeled vaguely as indie. And how about the Lemonheads? Or PJ Harvey that sounded rather more like bands from the States?
Well, pigeonholing is always a bit silly thing to do, but I'd think there are some things we could somehow generalise. Grunge had that Mudhoney's and Dinosaur Jr:s distorted bass sound, while indie had rather soft pop and sometimes psychedelic elements. I don't know were there other more peculiar sub genre labels about indie in other (your) countries, but I've heard one: "dream-indie", which I think describes some bands quite well.

Also, I think Shush said quite interesting thing there in the "Australian bands" topic about a history before the indie movement in late 80's in UK. The SAW, I mean... But how did it happen in States before the grunge? One thing I've heard was that the Melvins were seen as some kind of start, or early inspiration to some of the bands in start of 90's. If someone has any clue it would be nice to hear.