Adobe Digital Editions on Mac OS & Sony Reader

It's possible to use Adobe Digital Editions as an ebook downloading and sorting portal on a Mac. If your Sony Reader has been authorized for use with your Adobe account (this has to be done on a Windows machine with the latest Ebook Library Software AND Adobe DE, and, additionally, your Reader needs to be up-to-date on its firmware), then you can drag & drop ebooks from you Mac onto the Sony Reader, which just appears as a mass storage device when plugged into your Mac. This blogpost does a pretty good job of explaining. I'm also grateful to this site for exposing me to booksonboard.com.