A11Y Style Guide is a handy reference for how to mark-up your web documents accessibly in HTML + CSS.
Dear Developer, The Web Isn't About You - a beautiful tirade for and against the way we do things on the web today.
A Theme Switcher: now this looks like the perfect way to create a high contrast version of your site:
Unfortunately the filter property isn't widely supported yet, and there are a few caveats that need addressed, but it looks like a really lightweight method.
Bryan Garaventa discusses the changes proposed in the new W3C Candidate Recommendation for ARIA 1.1 in a four part series, beginning with Differences between ARIA 1.0 and 1.1: Deprecations & Additions.
Nielsen Norman Group call out a few big website owners in their recent article Top 10 Enduring Web-Design Mistakes.
Your Body Text Is Too Small says Christian Miller, and he's probably right. He makes some good points about legibility versus readability and provides some examples of top sites that use pretty large text sizes on their sites.
Dos and don'ts on designing for accessibility - six useful infographics to help guide your decision making when it comes to accessibility considerations for deaf, dyslexic and blind users and those with autistism and motor-disabilities.
If you have no idea what it's like to deal with Dyslexia, here's a simulation that demonstrates the sort of challenges a dyslexic person may face on a web page.
It may have been an April Fools' joke but the message can still be read in reverse and appreciated. The Nielsen Norman Group produced a cracker of an article called Difficult Designs Are Better (for Humanity) that highlighted various usability concerns, like how important it is to challenge your visitors by making navigation "joyfully suprising" and give nothing away upfront and instead force your users to go deeper on your site to find more. Brilliant!