BR,
Yes, I do prime them using that excellent plug. Sometimes the ISBN extracted is wrong (not sure why), sometimes the metadata list contains a bunch of entries that are foreign versions of that book and sometimes I don't get a number out of it at all (djvu, scanned pdf etc).
I'll try to find kiwidude's post on metadata! Thanks for a pointer. I'd really like to learn how Calibre picks entries during mass-download of meta. I have a whole bunch of books and doing it all manually just takes way, way too long. I don't mind doing it for few books but doing it for 30-40% of them is just a giant pain. I just don't want to end up with a bunch of mislabeled books. I'd prefer my current way of finding things (search of filenames) to having books completely mislabeled as something else and not being able to find them anymore.
PS: I've PMed kiwidude few days ago asking about how to write a plug for a site (academic books one) and he gave me a few pointers! I'll try to write my own plug in next few weeks. Don't want to bother him again
