Was the bump in the 1970s due to the commercialization of early teaching machines? And similarly, was the increase in the late 1990s onward a result of computer-based instruction? Or was this the influence of the Gates Foundation? (Or both?)
The OED dates the word "personalization" in print to the 1860s, but the particular definition that's used today -- "The action of making something personal, or focused on or concerned with a certain individual or individuals; emphasis on or attention to individual persons or personal details" -- dates to 1903. "Individualization," according to the OED, is much older; its first appearance in print was in 1746.
Something happened in the 1960s, according to the Ngram data at least. We see a peak of "individualization." "Personalization" took off dramatically a few decades later, circa 1995 and 1996. Was this related to the Web?