PPK describes the this keyword as a reference to the owner of the function we are executing, or the object that a function is a method of. He then compares how attaching a function to an event in two different ways affects what the this keyword references.
Tim Caswell describes the JavaScript variable 'this', which is about current scope and current context. The only way to create scope in JavaScript is through function definitions, and in most cases the context is the receiver of the message (the object before the dot in the method call). He also talks about approaches to controlling what this references with call, apply and bind.
Jonathan Snook demonstrates when JavaScript passes by reference or passes by value. Essentially, primitive types are passed by value, objects are passed by reference. Passing functions however, makes things look like a pass by value if the this keyword is being used in the code. Snook offers workarounds to this by passing objects so that the context is correct, or using the call() function to ensure the context is correct.