I cannot think of a single product/thing/whatever that accomplished the goal you mentioned.
The "dent in the universe" bullshit is such hypocritical thinking that it makes me sick.
Really? Let's look at his goal again (my emphasis):
> make a double-digit percentage of humans on Earth happier, cleaner, safer, healthier, or more efficient.
Hey, a union! That makes his claim a lot weaker and far easier to justify. Now we'll be generous and ask for 10%, the lowest double-digit percent, of the population. What's a candidate technology that immediately comes to my mind in the past? The microcomputer. Let's suppose the microcomputer revolution didn't begin until 1975. The world population in 1975 was about 4 billion, ten percent of that is 400 million, which is a little more than the current US population. Do you think that over the last 40 years, the microcomputer has not achieved an improvement in any of happiness, cleanliness, safety, health, or efficiency for just 400 million people? What planet are you living on? I'd say the microcomputer even satisfies the intersection of those improvements as well, but that was not the parent's claim for a goal.
Maybe it's hard to achieve the goal over a short timespan you say. Let's pick a more modern example, then. If you believe Facebook, they have over 800m active users worldwide, which satisfies the 10% barrier quite nicely for our bloated 7 billion world population, and they've been around for less than a decade. Are you going to say that Facebook doesn't improve any of happiness, cleanliness, safety, health, or efficiency for those active users? Come on. I don't particularly like Facebook myself but I wouldn't make such a negative claim.
Ed: looks like I was beat to the punch on the obvious example of Facebook.
I know, it is a saying, but take a look at "important people" that lived 2,000 years ago. How many do you know? 5? 10? What about the other millions of people?
Thing is, this whole "dent in the universe" thing leads to discussions that are pretty close to comparing cock lengths. "My goal is so much more worthy than yours - I'm making a dent in the universe", which I find highly hypocritical.
I believe there's no fundamental difference between the "dent-in-the-universe-webservice" that some people claim to develop and, say, lolcats. At least the latter made millions of people laugh for a moment.
After seeing this answer there is only two possibilities; you are either trolling or have a psycological condition that makes you take any statement way too literal.
When people talks about a "dent on the universe" they usually mean people in the same time and age in the planet earth.
Lets talk about Google.
Productive in absolutely all possible ways. Cleaner? Yes Safer? Yes. Happier? Happiness can't be a metric because its way too subjective.
Cleaner? People don't need to go to a public library for any question they have; so yes. Also many people used to print before they know they could find anything anytime on the internet; so studying required a lot of printer ink and paper.
More productive? In the term that you search absolutely anything related to your field and you find it instantly; sometimes you don't even have to click the page because the summary already answer your question. The pages saved in cache are awesome feature.
Safer? People relies on their own gut much less than before; instead they do a quick search in Google about how to do something wish usually includes safety recommendations about the task.
I know I am giving Google properties that are part of overall internet; but if a house doesn't have any entering door It is useless doesn't matter how full and complete is inside.