I take great heart in the fact that our local branch of Waterstones has a large and well-stocked Crime section ... as well as a separate section called Cosies.
Now I shall shy away from defining a "cosy" mystery, only saying that many would name one major "cosy" author - Agatha Christie - and also be able to read the jacket blurb and say "Yup ... it's a cosy, all right!"
I just think it's sweet that a major chain has a particular section for this time of crime fiction. The trick is in the judging of what comprises of the type. I've no complaints - I'd always look through this section as I would through a hypothetical "hard boiled" or "serial killer" fiction section.
I think I'll also let the authors know of their novels presence in the section; they might disagree with the label. I would also like to point out that about 80% of the titles are independent publishers - here in the UK, this is largely US publishers such as Poisoned Pen Press or Berkley Prime Crime. However, is this an indicator of the reluctance of major "mainstream" publishing houses to bother with cosies? Since Waterstones has seen fit to make a section devoted to them, perhaps they're missing a trick!