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.
Maybe an analogy is due. In the car world there are all kinds of people who strap on after market accessories to make their cars faster. These people are in the "fad" part, where as the underlying "advancement" may be decades old.