I will second the
other duck
Inconsistent is the best I can say. And that is for a SINGLE source. Use multiple sites
Who is to blame? Everyone from the book Author, Publisher to the Fan who contributed to review sites . Even YOU. We all want OUR metadata in
just a certain form. Never mind, that others use a different one.
We use OUR version
Visit the index of plugins. I use a number, but Import List is one of my Fav's for pre-populating (wish list) or updating the Library.
Don't even start on Series naming.
Tags? Some even think their name should also be a Tag. Toss in the Kitchen sink seems to be the rule some Indies use.