
I had fun setting up my LibraryThing library and will probably continue to add titles.
That being said, I've been using LibraryThing as a Readers' Advisory tool for a while now. What works great for that purpose is the list of books suggested. So if a customer tells me they liked Richard Russo's Empire Falls I search that in LibraryThing and see what other books are suggested based on those who've listed Empire Falls in their library. Explaining it takes far more time then the actual searching and when I use the results in conjunction with other resources, it works very well. I find it especially useful when I'm looking up books I'm not familiar with. Invariably, I'll find a title or author I am familiar with in the results list.
Where it doesn't work as well is with the lesser known works or with authors who've got a lot of books under their belt. For the latter the lists will end up containing many of the author's other works and that isn't helpful if I'm looking for further reading.
And while I find the Unsuggester fun the most practical use I can find for it is to use it as something to show customers to get conversation started. And if I were Queen of the Publishing World this is the book I'd provide for LT novices.