In the blog post on Context Actions I showed how to use the Extract Method context action. The last step - renaming the NewMethod - was a stopgap measure because Link Mode didn't exist in Beta 1 yet. But it is available in the current builds on the build server.
So what is Link Mode? It obviously links two things: in the case of Extract Method, it is the method declaration and the call. This translates into the method declaration being highlighted, and the moment you type, the method declaration and the call are updated with your naming changes to the method.
To give you an idea of this in action, have a look at this really short screen recording (no sound):