Sirenia Digest is simply designed (it's a Word document with a few images in it, basically, that has been converted to PDF) and the stories in it are always a little raw and personal. There's no editor telling Caitlin what to write; she just writes what she wants. This allows her the perfect medium to experiment and practice her writing.
Often, the stories don't have much in the way of traditional narrative. Such is the way of vignettes. They paint dark, disturbing, usually erotic images, and then move on. Perfect reading for this sound bite generation, methinks.
The power of Sirenia Digest, too, is in what it offers the creator. I'm not sure if Cailtin has any overheads, but writing two vignettes a month should be easy enough and, if she's getting $5 per month per subscriber, it's a decent amount of petty cash. All she'd need is 10 subscribers to pay for satellite. 100 subscribers for a month's shopping. 1000 subscribers for a (cheap) car. That's a nice, easy earner for any writer, for only two stories. To earn the equivalent of a pro sale on each vignette (which are usually under 10K words), she'd only need 100 subscribers. Since most of her stories are around the 2K mark, she'd only need 40. Which doesn't sound so bad. I'm half tempted to do something similar myself. Of course, I'm not Caitlin R. Kiernan and I don't have Vince Locke illustrating my work, but it'd help pay the bills.
Maybe in the future writers will support themselves in this way, bypassing magazines and publishers altogether and selling direct to their readers.
It's a quaint thought, isn't it?