Websnark is or was a blog that has seen as one of the most (if not the most) in-depth and detailed sources of Webcomics analysis. It has two main writers, husband and wife Eric and Wednesday Burns-White, who tackle different areas of the genre. These days the site isn't quite abandoned, but it only gets new posts once or twice in a blue moon.
Like Television Without Pity, it provides snarky commentary and reviews on webcomic plots and structure. It academically pulls a webcomic apart by the tropes and points out everything good and bad about them. It is considered by many artists and creators a sign that your comic has made it if it is mentioned on the Websnark front page. This usually results in a massive boost in its readership, as at its peak Websnark received over 60,000 hits a day.
Oh, and it's not actually intended to be a webcomics blog - just a site where the Burns-Whites post about stuff they find interesting. It just happens that they frequently find webcomics interesting.