I came across this book on a list called Good Reading for Hard Times but I'm afraid it didn't work well for me. It is set in in 1997 at a company of scientists called High Tech; the narrator is trying to isolate how fads spread. Each chapter begins with a brief description of fads through the years, from tulips (1600s), mesmerism (late 1700s), dance marathons (1920s), mood rings (1975), to virtual pets (mid-1990s). I did enjoy hearing about the fads, though I had some argument with when/if some of them ended: the influence of Dr. Spock's book extended well beyond 1965 and I still like angel food cake (1880-1890).
The least appealing part of the book for me were snarky take-downs that were everywhere: the complexity of ordering a latte, company administrators and their funding forms, incompetent low level employees in the company, librarians, wait staff.
I did learn about the word bellwether. In this book it refers to both the lead sheep of a flock and a trendsetter. The bellwether was historically a castrated male sheep that had a bell around its neck. The term comes from Middle English words for bell and wether (castrated sheep). The wikipedia entry about bellwethers describes the use of the term in politics. A geographical region that reflects the trends of the country as a whole is a bellwether. For example since 1896 Ohio has voted for the person who won the presidency every year except two (1944 and 1960). This doesn't mean Ohio is a trendsetter; in politics the bellwether reflects a trend, rather than setting one. Perhaps this explains why I imagine I would have spelled the word "bellweather" as I think of it as a weather vane. And then I didn't know anything about wethers.
The author mentions the cook skin cap fad of 1955 which grew out of the Davy Crockett television show and included marketing of lunch boxes, bow and arrow sets, jigsaw puzzles, and of course, the cap. So I pulled out the cap pictured here that Mr. Booklog purchased at the Alama in the 1980s while at a library conference in Texas. We had been unable to purchase one here in Virginia to fill the Christmas wish of our daughter. She wore in constantly, but the fad didn't reignite.
Though I can't find the reference now I think the book mentioned pineapple upside down cakes as a fad. That moved me to buy some pineapple rings and cherries and soon I will get out my iron skillet and make a cake. So I guess I was diverted by this book, but in equal measure I was irritated by the unpleasant tone.
Connie Willis, Bellwether, Spectra, 1997, 247 pages. Available at the UVa and public libraries and from Amazon.