I'd count them as an advancement as soon as they are added to the body of knowledge. XMLHttpRequest has been around for nearly a decade. A decade ago the "advancement" was there. It took almost 10 years for the fad to build up. If someone wants to know the fads (AJAX) just read prog.reddit.com and you're all set. If you want to know REAL C.S. advancements you'll have to dig a bit deeper into the literature.