I know of a couple of authors who have done this. What happened is that they didn't think the story through before they started writing. Since they didn't have an outline or a more than a vague idea of where the story was going, plus the fact that they were posting it as they wrote it, they painted themselves into a corner. Things that they had written in earlier chapters eventually prevented them from taking the story where they now wanted it to go. Since they couldn't figure a way around the problem, they just stopped writing the story.
I think this points out two different approaches, one of which you should use before writing. Either have a detailed outline of what you plan to do in the story or write most or all of it first, before posting. I actually do a combination of both, but I primarily like to write all or most of the story first before posting, because there have been many times when I have gone back and made changes to earlier chapters (some minor and other times major changes) to get it to fit in with an idea that came to me later.