Lots of good stuff happening in math blogging!
- Matt Baker is blogging! Lately: an appreciation of Robert Coleman, and Riemann-Roch for graphs.
- Frank Calegari is blogging! Actually he’s been blogging for a while but there’s tons of good stuff on here lately. Two recent posts that tie in closely with my own interests: The congruence subgroup property for thin groups, and The thick diagonal, in which Frank’s student Vlad Serban solves a puzzle I asked about, and much more besides. Also, Cheeseboard still wins.
- Adriana Salerno is blogging! Mostly about the profession and specifically the situation of young researchers in math. I like this post about collaborator visits because my old friend Leila Schneps, who taught me about the fundamental group, guest-stars in it!
- And just so it’s not all number theorists: Afonso Bandeira is blogging! I don’t even know this guy, but he’s writing tons of interesting stuff about problems in what I like to call “applied pure math,” questions about geometry of large sets and classification and convex relaxation and embeddings of metric spaces and etc. and etc.
Quomodocumque 
I still can’t imagine that Cheeseboard is preferred over Sliver. Oh well.
When in the mood for something random, you might enjoy Djalil Chafaï’s blog Libres pensées d’un mathématicien ordinaire (written in English).