python

Joshua Bloch's Google Tech Talk on how to design good APIs and why it matters, with concrete principles and examples. It treats every programmer as an occasional API designer.

Douglas Crockford's 2009 Google tech talk on the good and bad parts of JavaScript, based on his book. He argues for using a reliable subset of the language and avoiding its flawed features.

Cal Henderson's DjangoCon 2008 keynote, "Why I Hate Django", is a funny critique of Django from a Flickr architect. It touches on scaling topics such as database replication.

Robert Martin's RailsConf 2009 talk looks at why Smalltalk lost out despite its technical strengths. He draws lessons about language communities and arrogance that he argues could hurt Ruby too.

Cliff Click of Azul Systems gives a Google Tech Talk on running Java business applications on a machine with about a thousand cores. He covers hardware and software codesign, including garbage collection hardware and the JIT.

Paul Biggar's Google Tech Talk on compiling and optimizing scripting languages, drawn from his work on the phc ahead-of-time PHP compiler. He covers runtime typing, aliasing and code generation challenges, and argues AOT can compete with JIT.