There was a lot of discussion about my question last week. I had introduced the idea that my grandmother always made a distinction between quilts and comforters. For her, a quilt was something that was pieced and then hand quilted on the frame. A comforter was either whole cloth or simply pieced but they were tied at intervals, usually with yarn.
For most folks it seemed that there is a modern interpretation that conflates comforter with duvet. Most said that a comforter had higher loft, fewer stitches or ties and was generally purchased in a store. There was also general agreement that a quilt was pieced and most agreed that it could be either quilted or tied. If there is some reason for a distinction, it gets a little hairy with whole cloth, although I can't imagine anyone would refuse to call a whole cloth with fabulous stitching a quilt.
The bottom line from my unscientific survey is that most people don't much care if there is a distinction. Furthermore, I am going to start suppressing the little twinge that occurs when I call one of my tied comforters a quilt.