Jill Walker in Norway wrote this definition on her blog.

“Weblogs are serial and cumulative, and readers tend to read small amounts at a time, returning hours, days, or weeks later to read entries written since their last visit. This serial or episodic structure is similar to that found in epistolary novels or diaries, but unlike these a weblog is open-ended, finishing only when the writer tires of writing (see narrative structure). ”