An annotated list of interesting things on the Internet:

The Monster (Grognor)
"It has many names: akrasia, apraxia, weakness of will..."

Harrowing and lucid view of mental illness from the inside. Echoes of DFW’s “The Depressed Person”.
Long Now and extreme conscientiousness

Stand-out essays:

The On-Line Encyclopedia of Integer Sequences®
Enter numbers, receive math

Essential reference for solving problems with combinatorial aspects. Also fun for aimless browsing. It can prove especially useful due to the sequence generalization of Richard K. Guy’s Strong Law of Small Numbers.

Cosma Shalizi's notebooks
Gleanings from readings in statistics, physics, and culture

It’s convenient to be able to point to Frequentist Consistency of Bayesian Procedures to indicate exactly what I mean by that phrase.

Come On Slam It Off
Taylor Swift vs Quad City DJs

It’s hard not to be familiar by now with the genre of Space Jam mashups, which are loosely curated and collected at r/comeonandslam. This is a strangely noncentral example to pick out, given its numerous deviations from convention: absent “everybody get up, it’s time to slam now” intro, interpolation of Quad City DJ’s other hit C’Mon ’N Ride It (The Train), posting on Vimeo, image manipulation with Bugs Bunny rather than Charles Barkley, etc. But it’s technically solid, sounds flawless, and I can’t resist the video that recapitulates the creation of the track as it is being listened to.

Slate Star Codex
That around which the LW/Rationalist diaspora has organized itself

Has perhaps the best comment section out there presently, although it is showing strain.