Looking for examples of small steps taken that had huge ramifications for society.

Medicaid/aire and how it desegregated hospitals in the South!

In the early 1800s, a man in New York tinkered with building materials and created a hydraulic cement that was better than any other that was available in the US at the time. This material enabled the building of the Erie Canal, which in turn caused the rise of New York City as America’s largest commercial center.

Source – Bill Bryson, At Home. Bryson also speculates that the absence of the Erie Canal could have led to Canadian economic dominance over the US, via exploitation of the St. Lawrence River instead.

If you are interested in some less contemporary examples, I recommend Connections by James Burke (both a book and TV series). He presents several examples of how relatively minor innovations caused chains of events culminating in major societal changes. (One of his examples was the horse collar.)

Compulsory education. Having a high percentage of the populate become literate changed society drastically. A century ago, most of the population was illiterate…

The internet?

I came on here to say reliable birth control- changed the economy, gender relations, family structure…everything.

This one.

Bacteriological theory and antibiotics - it turned common and fatal diseases into easily treatable ones.

The Surgeon General’s Report - It’s turning smoking from a harmless pastime to a social taboo. Smoking rates are significantly down from the WW2 rates, and each passing year it becomes increasingly socially unacceptable. This seems like an example that is underway and that has had some ramifications, but some still probably lie in the future.

The railroad - caused a dramatic increase in mobility. Now, people whose parents were born, raised, married, raised kids, and died in the same town could go to the city or another town whenever they wanted.

There are some really great ones here. Two more that come to mind are eyeglasses and rap music. Eyeglasses allowed society to benefit from the learning of more people for longer periods of time. Rap music has provided an avenue for poor urban blacks to do well and amass wealth. (Although it does have its downsides, as well.)

Sanitation.

How about the simple one of making doctors wash their hands before/after surgery? It dramatically affected patients living through surgery.

It was one thing to add seat belts to cars but another to actually get people to wear them. There was a rather extensive ad campaign in the 70s to convince people to do just that. It wasn’t until most people did use their belts that laws requiring their use were passed. They probably couldn’t have been passed earlier.

Attitude change about drunk driving also took an extensive ad campaign. I don’t know if the OP should count the ad campaigns as “small steps”, but that’s his decision.
Along the same lines as fluoridation and iodized salt is the addition of vitamin D to milk and folate to bread.

EXCELLENT! This gets Roadfood’s idea closer to what I’m looking for. It has to do with “attitudes”. Whereas it was odd for us to wear seatbelts in the 60s and 70s, it’s now odd not to. Same with drinking and driving. We used to do it all the time when I was in high school without an iota of a thought of being arrested. Now, if I think I’m going to have more than a half glass of wine with dinner I take a cab.

There’s been a seismic shift in attitude. Great! Anything else? Maybe something not as overt?

Both The Pill (and its succesors) and compulsory education have been mentioned. Both involved huge changes in people’s attitudes, in power relationships and imbalances, in social and geographic mobility: my great-grandfather wouldn’t have left his hometown if it hadn’t been for the draft, and his father used to deride the wife for teaching their sons to read (“reading is for people in skirts!”, that is, women and priests); nowadays kids in that same depressed area of Spain know that they will eventually leave town for, at a minimum, two years of trade school in the nearest big town - not because they need it to be farmers or have small hotels, but because nowadays education is both valued and accesible.

That same great-grandfather later got a 4th-grade education at the same time his firstborn was in school: the son went to school during the day, the father in the evening, they did their homework together. Nowadays, governments in the first and second world are worried about immigrant literacy and about practical literacy: basic literacy is taken for granted. When my great-grandfather ended his draft and signed up to become a cop, what was assumed was iliteracy: the form the recruiting officer had to fill included questions on “can you add using paper and pen? substract? do you know the four rules (±*/)? Can you read your own name? Can you write your own name?” Nowadays, what job asks that?

The Special Olympics. Eunice Kennedy Shiver started them in her backyard, and was told “those people can’t take competition.” It really changed society’s attitudes towards the disabled.

Taking away the stigma of being handicapped and/or mentally ill. People that would have been locked away in an institution 50 years ago are now productive members of society. If you’ve ever read Marie Killilea’s book about her daughter Karen, she was told that babies with cerebral palsy hasd no intellect, and consulted 11 doctors before finding one thst could help her.

Child Safety. My brother and I used to ride with my dad in his Corvette convertible. With the top down. With me wedged between the two seats. Thought nothing of it. Now, you have to check the internet to figure out what kind of restraint you’re supposed to be using based on age, height, weight, and phase of the moon. It’s no longer debatable whether or not to use a special restraint, just when it becomes “safe” to move to the next stage.

Used to be you were a bad parent if you didn’t get your kid a bike, now it’s if you let them ride without a helmet.

There are some really great answers here. Thank you all!

dope 1: “what should we do?”

john galt: “remove income taxes.”

dope 2: “but how will we pay government workers?”

john galt: “fire the government workers.”

Sorry.

Would the private member’s bill seeking a moratorium on sentences of death for murder in the UK count?

Iodine is added to water to prevent goiters, not mental retardation. (I imagine there aren’t too many people on this board who have seen someone with a goiter. When I saw them as a little kid, I found them scary.)