My co-guest blogger Scott Story (a pseudonym of some kind, surely) posted yesterday with some tips about long form comics on the web. While his advice has some merit for certain types of webcomics, I'm not at all in agreement that they are general rules or even good rules.
Some of his tips are all too focused on a webcomic that is based on the single episode/strip/page as the primary structure of the narrative. This is the traditional model that so many webcomics seem to work from, the comic strip model. Scott suggests each episodes have a "beat" and a "cliffhanger" the same type of advice you see in action when you read classic comic strips, particular those in the adventure genre: Roy Crane, Alex Raymond, Milton Caniff, etc. But I don't think this applies to webcomics working in more of a "graphic novel" mode where the work is considered as a single story/book not an series of episodes. Off the top of my head, I can think of a few webcomics that work in this latter mode, such as Family Man or Finder.
I imagine a lot of these tips (not having long scenes, keep fights short) would not apply for anyone working in the manga vein either, where scenes and even actions tend to be build up over a number of pages. Imagine Vagabond with short fight scenes! (It'd be a couple thousand pages shorter, that's for sure.) Sometimes it takes a number of pages to build a complex and engaging scene with depth of feeling or narrative content.
And some of the tips are just sad. "Don't dwell on depressing subjects overlong." Depressing subjects are a hallmark of art (particularly literature and film). Who wants upbeat comics all the time? Not me. Scott notes: "People read webcomics for enjoyment, and they don’t want to be brought down with really dreadful stuff." This flies in the face of the popularity of all kinds of art with "depressing" or "dreadful" content and the idea of cathartic release. "Use flashbacks sparingly." Flashbacks (or other time shifts) are a hallmark of narratives, going all the way back to Homer (huge swaths of the Odyssey is in narrated flashbacks).
The explanations for the advice are all about the readers and seem rather condescending. "It's hard for the reader to keep track of scenes within scenes." "If a scene is too long readers will lose interest." This kind of coddling to a dumb downed reader seems like a great way to make really dull and conventional comics (Note: I have not read Scott's comic. I glanced at the home page when I read that he was guest blogging this week, but it looked like a superhero comic so I didn't go any further.)
To a certain extent I can agree with his advice about double page spreads not working on the web, though again, this will depend on what you are trying to do. If you are posting your comics in large chunks as pdfs or through some kind of reader (see the Arthur Magazine reader, or check out the readers used by Viz at their various online manga sites) then spreads can (and do) work.
My advice: Study good comics/art/literature/films. See what works, not just for one genre or style or form, but for different types of work. We have too many comics already following the model of the comics of the past without looking outside a narrow field.