So here's what I've learned in my own project so far....
Mind the Thorns is a web serial that I wanted to make available as eBook and print "Issues" of 3 Chapters. They were targeted to:
1) People who wanted to support the webnovel by buying something to pay me for the work.
2) People who really prefer to read print editions in hand
3) People who want to collect the issues because the book is just that cool.
I was working on the model of a comic book or a graphic novel as I did this. I was also trying to stay on a formula of posting a chapter a week, and then having an issue available every 3 weeks, with a one week delay between posting a chapter and sending the 3 chapter issue to be printed. MtT is reader-directed so the most important thing to me was to drive traffic to the website to get people engaged and voting, not just sell copies.
I took it a step further and registered the first two issues on Goodreads as "books" and started to try to use Goodreads marketing to publicize the project and get some interest. I also put the first issue up for "Giveaway" and received 200+ requests for the 10 copies I made available.
Here's what I learned:
1) Despite the fact that the giveaway was stated to be an "Issue" of only 3 chapters many people expected a 200 page novel and reviewed it down because of that.
2) Very few people want to buy a 3 chapter issue on Amazon. I have been able to "sell" them at signings and craft shows but I am selling them at a loss so it's mostly me giving them away to get interest and hoping that ad revenue makes up the difference.
3) Smashwords does not permit the posting of Serials, only "completed novels". While a novel does not need to resolve all conflicts, a three chapter "part" of a longer work, regardless of how it's priced, is against their TOS. I was asked to remove the issues from Smashwords until the entire novel is finished and ready for general consumption. While I understand, this does little to drive traffic to the polls that make the Reader Directed model work. I was a little miffed about this given that you can buy short stories there and a novel does not need to have a clear "end" (at least not as I might define it) but, meh, whatchagonnado?