Slightly more rooted?

I found out recently that my father's side of the family is nearly 100% German immigrants (dating to the 18th and early 19th century, respectively), which makes me 50% German (or so). My mother's side is some mix of Polish and Slavic/Hungarian. Anyways, some distant relative of my father's made an entire genealogical chart of my grandmother's family that traces back to an immigrant born in 1722 in Germany named Johannes Reiter. Then the rest of the chart maps dozens of descendants, the majority of whom never left a 20 mile radius of Reading, PA, USA.

As a historian, this leaves with a larger question: Since when (and why?) did everyone get so excited about genealogy that tracing back the roots of a relative was of the utmost importance? (I'll admit, my senior project in high school also involved tracing back my family on both sides, and I was excited to see civil war service records of my great-great-great (?) grandfather, which my father found at the National Archives and Records Administration.) For me, tracing my family roots actually allows me to feel more "rooted" in a time in which people are highly mobile and many people end up moving away from "where they grew up" or, in my case, never had that place to begin with. For other people, it seems to me that they like to trace their roots for personal identity reasons as well, albeit maybe not for exactly the same reasons as me. In either case -- I'd be interested in looking at the changes in collective history / memory that have occurred over the past 50 years, as related to changes in identity, mobility, and other factors, such that so many people are so fascinated with genealogy.