Think of books, though. They're the best available counterpoint to what you're saying. People don't necessarily care about the author of a book, but they do care about the content of the book and its ability to piece together a larger idea.
Within forum post culture there's a built-in tendency for content to be fast and disposable. This makes identity relatively more valuable, because it allows a stream of posts to be put in context, just like with a book.
