Wikipedia (Jan 2001, so barely squeaked in)

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

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.

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.

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.

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).

My little girl.

Guys you're all wrong.

It's PornHub.

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.

CRISPR

Corona vaccines

Online Streaming

Online Maps

Wikipedia

Drone Warfare

LHC

Paris climate treaty

Those little straws with the filters inside that allow people to drink contaminated water right from the source.

I'm genuinely not sure that anything has been invented in the 21st century.

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.

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...

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.