The cost of Open Access

Here is a nice little review from the Economist of the current state of Open Access to scientific publications. The financial burden on the author is detailed:

There are, however, a few thorns among the roses. Traditional publishers are often skeptical about the business models of their open-access rivals, and they sometimes have cause to be. The Public Library of Science (PLoS), an American organization regarded by many as the flagship of the open-access movement, lost almost $1m last year. As a result, it is about to increase its charge from $1,500 per article to as much as $2,500, depending on which of its journals an author publishes in.

Since anyone can make their research available for free by self-archiving, presumably the added value is the "blessing of peer-review". But if reviewers are not paid, where does that money go? Anyone out there know?

Thanks to Beth for the link.