I'm also doing a serial, and I'm collecting links to other serials for my blog. I'll probably do a post about on them sometime next week. (I'll post here when I get it done.)
My serial is a promotional idea - I'm posting the first book THE WIFE OF FREEDOM (which is available on Smashwords and Kindle) at three chapters a week, to motivate myself to finish the sequel by the time I'm done posting the first. http://daringadventurestories.blogspot.com/
Later I hope to do some other serials. I have some novellas that would be good four chapter serials. I also have an idea for a series of novella-length stories that would be great as a serial too. The adventure stories blog could be a fun way to promote.
The one thing I can't do is what you're doing - post before the story is finished. I can't write in chronological order, so I couldn't start a serial until the whole story is finished. (Although for one of the shorter works, that could be a fund "nanowrimo" type challenge.)