What's the greatest invention of 21st century, in your opinion?

We are in a time where a single invention can rarelt be great. For technological development you need thousands of small inventions, each that use previous technological breakthrough through decades of research. And even great things we have, are just refinement and miniaturization of things we already had.
But if a single thing had to be said, I would say mRNA vaccines. Covid vaccines saved milions of lives, were developed in record times, and their technology could be used for HIV or even antitumoral vaccines.
- Came here to say it.
  The heroic inventor story is archaic.
- but the research began already back in the 60s.
  
  That's why I'm saying that a single invention that changed the world is not something you can easily find anymore.
  
  That's why I'm saying that a single invention that changed the world is not something you can easily find.
- Was going to say that too. Regardless of the motives and driving forces behind the incredible speed at which the vaccines were developed (i.e. certainly a similar urgency could be applied to other diseases killing thousands and millions in poorer countries, but there ain't as much interest in that), the mRNA technology proved quite powerful and an avenue to continue exploring in future research.
  
  People forget that the research behind those vaccines had been going on for 30+ years. What was accelerated was the trials and the gathering and analysis of efficacy and safety data. The actual vaccine technology had been in existence for around a decade at the time.
- The first successful transfection of designed mRNA packaged within a liposomal nanoparticle into a cell was published in 1989. "Naked" (or unprotected) lab-made mRNA was injected a year later into the muscle of mice.
  But on the other hand, first human test was in 2001

I gotta say mRNA vaccines. It's not technically a 21st century invention, but much of the work to make them viable started in the early 2000s. The speed at which the COVID vaccine got developed and widely deployed was honestly incredible and a massive W for humanity. I remember thinking a vaccine would be years away.
- Vaccines in general.
  
  Then we're very far away from the 21st century though.

My little girl.

Wikipedia (Jan 2001, so barely squeaked in)

CRISPR
Corona vaccines
Online Streaming
Online Maps
Wikipedia
Drone Warfare
LHC
Paris climate treaty
- CRISPR is the closest we get It might be the honorary winner since it was wasn't fully exploited until the 21st century, even though it was cloned and being used in the 90s.
- Great list! I would also add to this PCR, the technology that allowed us to map the human genome.
  
  PCR has been around since the 80s, though it has continued getting more efficient and cheaper

Hard to quantify, but stuff like PrEP (a drug used to prevent HIV infection) has probably saved a staggering number of lives across the globe, same with the yearly influenza vaccines.
For a more personal one?
I'd say the innovations to bikes, which have been staggering since 2000. Downhill mountain bikes have had staggering changes that make them lighter, faster, stronger, and way more stable, and they look dramatically different to their 90s counterparts. Stuff like dropper posts, modern full suspension, tubeless tires, disc brakes, and massive cassettes make them incredible. You can roll over a cantaloupe-sized rock at 20mph and the bike will just take it without you being ejected over the bars.
Ebikes have totally changed the calculus in hilly cities, even in flat ones to some extent. Being able to effortlessly bike 45 miles and not be totally thrashed the next day is such a gamechanger, it's actually beyond belief. My car has been largely collecting dust because most trips day to day are under 45 miles. And it takes pennies to recharge vs $90 or so to refill the tank.
Bikes already help take tons of cars off the road worldwide, but ebikes could really help extend people's ranges, particularly if they would normally drive otherwise.
- getting from my house to my office on my old road bike used to take 45 mins and I'd be sweaty when I got there, and the idea of 45 mins uphill after work used to make me wanna off myself. Since I got an e-assist its 25 mins and I'm like lah de dah meep meep
  
  Dude, same. My e-bike is hands down my favorite addition to my life. Where I had to deal with the train or the traffic and the waiting and the crowds, now I hop on my bike and cruise lah dee dah meep meep but when I am running late for work I’m all like eeeer vroom vroom skrrrt and I bomb down the bike path like aw yeah. And I’m honestly rarely late anymore because I get everywhere in about half the time it would’ve taken me otherwise.

Those little straws with the filters inside that allow people to drink contaminated water right from the source.
- One of those saved my ass on a solo, overnight kayaking trip. I mostly brought beer, ice and food in my tow-behind cooler because I had a Life Straw.
  The trip was hell, most difficult thing I've ever done, wasn't sure I'd make it out. Was good on water until the next day when I finally broke out onto the main creek.
  Cut the top off a can and sucked down 7 refills of creek water. Tasted exactly like warm, flat, tap water.
  
  Look into Sawyer water filters. Much easier to use than lifestraws, last longer. Pressure instead of suction.

I'm genuinely not sure that anything has been invented in the 21st century.
- Many things that were conceptually conceived in the 20th century didn't become viable until the 21st, such as OLED, VR and AR, raytracing, telesurgery, a whole slew of types of artificial organs, a gigantic amount of miscellaneous advancements in integrated circuit fabrication, alternative vehicle fuel such as methane, hydrogen and rechargeable batteries; maglev trains, innumerable safety improvements in aviation, mRNA vaccines and so on and so forth. I don't think it's fair to credit all that stuff to the 20th century, unless someone somewhere saying "be real cool if we could do that" counts as inventing something.
  
  OLEDs were built in 1987 I saw my first VR demonstration in the 90s (and it wasn't cutting edge then). I saw my first AR demonstration then as well as part of an undergraduate engineering fair. And so on. I just looked up maglev trains - in commercial use since 1984.
  I don't disagree that there hasn't been refinements, improvements, or commercialization of technology, but there hasn't been a technological leap or invention that I can think of in the 21st century.
- Yeah, I was thinking about it and then asked here. It seems like most of nice stuff was invented in the 19st century, and in the past 24 years we just improve it.
- Only birds.

Guys you're all wrong.
It's PornHub.
- It's obviously bofa
  
  What's bofa

The 21st century has been mostly focused on finding new applications of existing technology. A lot of things are changing in pretty much every aspect of life, but nothing is entirely new.
The internet has really changed the shape of our world, but, even though it really kicked off after the year 2000, it was invented during the 20th century.
Something to keep in mind is that humanity is redifining what counts as an invention, a lot of ideas are created all the time, so the bar has been raised significantly.
Also, we need to keep in mind how big corps have been killing innovation in the name of profit. New products are being created all the time, but they are bought by bigger companies and burried. This is happenig because these innovations carry a certain risk that an established company with a good revenue flow is not willing to accept.
Personally, I am excited about the field of Social Computing, it is still at its infancy and has a lot of potential. The main idea is to create alogirthms based on human interactions that solve real world problems. A few questions one may ask include: How misinformation is being spread, and what is the optimal way to fight it? How do we fight corruption and authoriative power? These questions have been approached by a lot of fields, but creating algorithms and proving their effectiveness requires a deep understanding of computer science.
- Personally, I am excited about the field of Social Computing, it is still at its infancy and has a lot of potential. The main idea is to create alogirthms based on human interactions that solve real world problems. A few questions one may ask include: How misinformation is being spread, and what is the optimal way to fight it? How do we fight corruption and authoriative power? These questions have been approached by a lot of fields, but creating algorithms and proving their effectiveness requires a deep understanding of computer science.
  I'm not a pessimistic person (I'm neutral), but the sinister implications are obvious.
  
  Well, I can see your point of view, after all computer science has been used for a lot of sinister things in our time. However, science is a neutral thing on itself, how we use it makes the difference.
  A great example are corporate social media vs the fediverse. While we can all see the good a social media platforms can offer, they way corporate social media have been shaped introduces a lot of problems. Given the circumstances I may argue they were a necessary step, but it's definitely time for change, and a lot of people (including us right now) are working hard for that change.
  Social Computing as field would study this change, how people made decisions, and how it influenced both their lives and the society we live in. It involves asking questions like: How the fediverse came to be? How the transition could have been faster? Or, How it can be used for the greater good?
  Of course, these questions can be shaped in an exploitative way like: How the evolution of the fediverse could stopped or slowed down? How the fediverse could be exploited for the gain of the few? etc...
  In the end, I believe the question is who is more powerful, a few people with a lot of money, or a lot of people with little money? Right now the few seem to have the upper hand, but if the access to resources is the only difference, then I believe that we can be optimistic as science and technology have always been about doing more with less resources.

Sodium-ion batteries are likely to be the obvious answer in another decade. Dirt cheap, abundant materials, competitive density.

Like it or not. The iPhone. It changed the phone and how we use it. I literally use my android phone for everything now, as a credit card, ticket, pc, social, gaming... some people get laid and marry thanks to them...
- Marriage and sex decline when societies adopt smartphones and the digital craze.
  
  Same as when the education level goes up. You know too much, I guess.
  
  Maybe sex with other people declines 😉

I mean we only have had fourth and things happen over time. So I want to say blue led but they existed before the century but just got the process such they can manufacture them. Native white ones are invented now but most white is using the combination method currently with the blue ones. Anyway if it counts I can't imagine how much energy this has saved even over halogens for lighting and then for dispalys to. I would hate to think how much fossile fuel we would be using if we were still on incadescents and crts.
- I didn't truly understand how much energy incandescent were burning. Grew up with nothing but those.
  One night my AC crapped out in my tiny apartment so I killed the lights except one in a far corner. The air was so still I could reach my hand out and sense the heat from a 60W bulb.
  
  the base of the lcd still gets way hot. makes me think they could be made even more efficient and hoping they will.

Can't tbink if anythung really, all we've done is refined some stuff butmaybe mRNA vaccines ?
Mostly we've just enshitified everything and/or made it disposable..From headphones to entire operating systems etc.
- I think medical advancement could be as dramatic this century was in the last. However, patent law is likely to hold us back

The reprap basically started the entire home 3d printer thing.

I cast: sudo shred *

The Internet Archive. Technically founded in '96, but didn't come into its own until the mid aughts. It is an awe-inspiring thing that corporate greed has been trying to take from us.

Although not very impactful yet, it think aerographene has the potential to be massive.

The fediverse. I can't believe nobody mentioned that yet.
After all, this entire website wouldn't exist without it, and we'd be all stuck on terrible, terrible Reddit (and Twitter, and... pretty much any centralized social media platform that are so well known).