Bjork released songs from the album on seperate app thingies first. And then she released it as one. And I don't believe they counted as sales for the album in particular. Just on the iTunes store.
And Jay there's several ways. The most popular way is by sending them to reviewers (notice that sometimes reviews come out before an album release?) who then leak the content to someone else to leak it on the web. The next way is the way we get lq snippets, which is someone who works at the label records from their phones and leaks it on the net. And Also sometimes labels make mistakes and upload albums too early (happened with Ciara)
Ohhh and I think sometimes computers get hacked and they take the albums from the computers and share the files

talk about security risk.