1) Dustin Diaz, writes about improving your "getXHR" Function. Using his code will create a very robust Function that finds the appropriate XHR Object, then overloads the executing Function so that you do not have to find the Object each time you call "getXHR". Thus, removing the cost of a constant operation from your getXHR Function and improving the performance.
2) Website-Performance.org goes live. This site is dedicated to providing good information, tools, and techniques for improving the performance of your website.
3) YUI is showcased by a design magazine, Smashing Magazine.