(BTW, for the purposes of this ramble, I'm using "drabble" interchangably with "ficlet" -- a very short one-shot story, anywhere up to let's say three thousand words, not just the more traditional 100-word drabble. I know some people are really picky about that terminology; I tend not to be. You have been warned.)
So, why drabbles? And are they taking away from people's interest in reading and/or writing longer stories? Personally, I am most focused on the collaborative novel right now -- it's my top priority, and when I have to choose between working on it or writing up random drabbles I'll usually chose the former. I'm more likely to look at the drabbles as an opportunity to take a break, clear my palate with something different. At least a couple of times a prompt has given me the opportunity to write up a plot bunny that I knew was never going to make a full-length story. And drabbles with enforced word counts are good practice for me; I tend to be long-winded, so I appreciate the ways a hard limit forces me to cut the fat and get to the essense of the scene (I hesitate to say "story", because I think very few true drabbles tell a complete story with a beginning, a middle, and an end). All of these are worthwhile ways to spend my time. Am I producing less on DSHnD? Possibly, but not in any way that's causing a negative effect, I don't think. I know I'm not spending as much time editing it compulsively, but maybe that's a good thing -- I can get into a cycle of overtweaking. Maybe it's better that I don't have as much time to poke at it, to rearrange the deck chairs.
But I do admit, the drabbles get much more feedback than my longer stories, and that's satisfying. When you write a story to order, you know that at least one person is going to read it, and chances are good that they'll review. I wonder if that isn't a large part of the attraction for some of us, knowing for a fact that someone out there cares that we have written this story. I parrot the party line that I write for myself and the feedback is gravy, but if that were really, really true, then why post it? It's not just for the warm fuzzies of a love note, or the useful feedback found in good concrit. I think it comes down to one basic thing: knowing that you have made a connection with someone through your writing. There's something very powerful about that.
I don't know whether drabble madness is taking away from production of longer stories or not. I'm not sure I'm qualified to comment on larger cycles and patterns because I'm so very new to the fandom (posted my first story in April 2005, made my first fandom friends about a year ago, but have only really been involved on a more connected level in the last couple of months). Some people just don't like writing long chaptered works; some aren't really good at it (or don't think they are, anyway). But people are still working on epics; I see at least two people on my friends list updating them regularly, not counting DSHnD. Now, I do think it makes people less likely to read longer stories. But I have a hard time blaming anyone for that; why should I expect someone to invest their hard-earned free time in a 46-chapter epic when they can get several quick fixes by blasting through half a dozen drabbles in a couple of hours? And is that a bad thing? I'm not completely convinced that it is.
I don't have any answers; I almost never do. ;) Mostly, I just enjoy musing on the questions. As always, I welcome any thoughts.
Edit: What do you know, fanthropology is having almost the exact same conversation.