LibraryThing I Love You!
OK so the corny title has surely been used before but hey: who cares! (NB I didn't use a question mark)
In speculating (again) about using ISBN barcode reading to get to grips with my domestic library I stumbled into LibraryThing, which I found rather appealing. You can bar-code scan straight into the form (they sell the rather cute CueCat) and there really seems to be some momentum in the Thing with Jo Public and, thanks to the involvement of Talis with some larger libraries too.
ISBNdb also caught my attention and from some initial dinking about with their data access API rather more attractive than using Amazon. Being the kind of person I am, its probably more likely that I'll hack something up of my own than use LibraryThing but its still something to commend, I think. For example ThingISBN makes real the rather abstract FRBR, which I blogged about ages ago (and does so with a nose clearly thumbed at OCLC). And is all just soooo mashable.
LibraryThing is only part of a trend that is blurring the online from the book-line. Whether you come at this from a "you won't ever replace books" or "if it can't be found online it doesn't exist" or .... doesn't really matter. More please!