...that don't have gigantic archives to slog through.
All joking aside, while I really like Schlock Mercenary (nominated for a Hugo recently!), I'm well aware that it's a very intimidating comic to try to read from the beginning (it's starting its tenth book). Heck, it took me a couple of weeks to slog through it myself (completely worth it, but maybe it's just me), and it's been a couple of years. Even significantly shorter comics like The Law of Purple (850+ pages, by my sister) can be difficult to sift through.
So in the interest of introducing the reader to webcomics that are young and good, I'll mention a few that I've recently picked up that are still in their infancy.
Alien Revenant: Once again by my sister. What can I say? (Well, this, actually, but it's not like I can talk about it too much, is it?) While The Law of Purple has been a learning experience for her, here she hit her stride at the beginning as an artist, and she's pushing herself even further. (Backgrounds are difficult for her, but she's made some beautiful ones here.) It's also full of her quirky sense of humor. And at under forty pages, it's still young enough to get through quickly. Updates M-W-F most of the time.
Lovecraft is Missing: For the fan of Lovecraft. Creepily funny, and at least as cryptic as Lovecraft himself. It's been mostly quiet so far, but I suspect, with the current page (which should be pretty darned obvious) that things are about to get nutty for a few pages. Under fifty pages. Updates W-F.
Runners: It started as an award-winning small-press print comic, and now it's a free webcomic. If you've never heard of it, now's the time to jump on the bandwagon. It's about some smugglers in a Star Wars-like setting (and not a bunch of athletes). Artistically speaking, really sharp and finished. Less than twenty pages up, although you can buy the entire first volume, already published. Updates M-T-W-R-F.
Afterlife Blues: The creators of Afterlife Blues previously created another now-complete webcomic, A Miracle of Science, in the words of the author "435 pages of mad science, space battles, robots, and true love." (I can say of AMoS that the robots, particularly the Pindars, are awesome.) Afterlife Blues is somewhere between scifi western and a mystery story, and thus has very different foibles. The art is occasionally a bit rough in terms of figure-drawing (and frankly, the least-finished looking of the art of any of these), but the backgrounds and setting designs are good. Currently under seventy pages. Updates M-R, slightly irregularly.
(Incidentally, my use of the "greatly belated book reviews" tag is for purposes of clustering these together tagwise with my other review-type stuff. The use of the "self promotion" tag has similar reasoning behind it.)