After the recent "why did you stop reading" thread, I thought it might be fun to look at it from the other side. What is it you like about your favorite comics/novels? What makes you eagerly await the next update? And try to be specific—"good writing" doesn't really mean that much.
For me, I'd say...
1) Character dynamics. I love seeing how characters interact with each other. I think a good way to highlight this in a story is to introduce your characters' primary personality traits as soon as possible, show them interacting with other characters, and allow those interactions to get more nuanced as the story progresses.
2) Interesting subplots. Obviously the main plot should be interesting, but a lot of my favorite webcomics also have plenty of subplots to keep my interest. These sort of subplots tend to develop over several chapters, which keeps me eagerly awaiting updates.
3) A good balance of comedy and drama. Of the two, I tend to prefer comedy, but I appreciate when a story can buckle down and get serious when the situation calls for it.
4) Similarly, a good balance between action and slice of life. For example, I enjoy a good superhero story, but I want to hear about their normal life, too.
So what about you? What do you like to see in a story? You can drop links to some of your favorite comics/novels if you like!