Go read the short comic His Face All Red, by Emily Carroll. It only takes a few minutes, but it's one of the most satisfying webcomics I've ever read.
I found out about it in the "best of 2010" edition of the 3 Chicks Review Comics podcast (which I also highly recommend if you haven't listened to it yet), where Maddy from When Fangirls Attack! picked it as her favourite short story of the year. (It was also mentioned on Robot 6 in November.)
It's a creepy little story, beautifully illustrated, that makes really great use of its online layout. I'm basically just repeating what Maddy said on the podcast, but you can tell Emily Carroll put a lot of thought into how it would be read. One of the interesting things about reading comics online is that there isn't any designated page size, so one page can be really long and force you to scroll down to reach the end of it, and the next page can be a single panel in the center of your screen. But I've rarely seen online comics fully take advantage of that the way the author does here. The experience of either scrolling down to reveal more panels or clicking through to the next page is part of the design and used to control pacing.
I haven't found a lot of info about Emily Carroll online. Here website is still under construction with a note saying it's expected to launch this month. Meanwhile, she's posting some nice illustrations and short comics on her blog.