One thing I totally don't get is why people would want to publish their story chapter by chapter. I could understand it if the chapters had any considerable length, but sometimes they're just a few paragraphs. Considering how short they are I'd at least expect that they'd be posted in quick succession. However, with a few stories it's years between a couple hundred words and the next.

What's the reason for that? The only one I can think of is that people publish their story before it's finished. That wouldn't work for me, but to each his own.
Are there other reasons, too?