Eugene Yan's personal 2021 year in review covering goal progress, writing output (34 posts vs. 48 goal), 10 talks given, angel investments in ML and cloud infra startups, adopting a rescue puppy, and building ApplyingML.com — a site collecting practical ML knowledge through papers, tech blogs, and practitioner interviews. Blog traffic grew 30% to 337k page views, email subscribers tripled to 2.5k, and Twitter followers nearly tripled to 6.5k.