I have more experience with situations where apps have already done the killing, than I have with being onboard with a killer app. I never used VisiCalc, for example, joining the spreadsheet revolution long after the field was already overfull with competitors (I certainly used some similar spreadsheet on the Dragon 32, but really got going with MiniOffice on the Amiga). People who ran the UK academic ISP JANET tell me that the X window system (originally on VMS) was the killer app for the Internet Protocol, and led to their implementing that over the favoured X.25 protocol, but I did not connect a computer to JANET until 2000, long after IPv4 had won out. I did use Deluxe Paint on the Amiga, but long after Andy Warhol had done the same and after other platforms had similar packages.
Really the only killer app I was in on the ground floor for was the most famously fumbled (though still incredibly successful) killer app in history: Facebook. I was working at Oxford University when Facebook came out, so once they expanded out to campuses beyond Harvard, I was in one of the earlier networks to join up. (You might not remember this from the early days of Facebook, but the site was segregated into separate instances that ran on different “networks”. A member from Harvard would see their Harvard friends, but nobody from MIT.) It turned out that Facebook was the killer app for university computer rooms, and before too long over a quarter of all email handled by the university’s central mail service was Facebook notifications, reminding people like me that that one Philosophy student I met in the pub once and decided to add to Facebook had poked me.
Where is the fumble? Well it turns out that Facebook was the killer app for mobile computing, and everybody noticed it except Facebook. It turns out that when you are super-rich, that kind of mistake is not existential—think Microsoft missing out on the early years of the public Internet, or Metallica opting out of music streaming—it is just embarrassing, and costs you quite a lot of that vast pile of money to catch up. In the early days of Facebook, it was conceived as a live status blog, in the style of the old “finger” protocol on UNIX. The placeholder text for my “wall” (the place in my profile for public posts) prompted “Graham is…”, and I would describe what I am doing in a way that made people believe that I had an interesting life, and was not the kind of person who sat in the computer room writing status updates on the web.
Mobile computing—once the ridiculously poor performance of GPRS was a thing of the past, the abysmal capabilities of WAP were transcended, and service providers stopped charging ridiculous figures for a few kilobytes of HTML—offered a new reality, one in which one could explain what “Graham is…” doing while Graham is doing it. Twttr/Twitter noticed this in 2006. Burbn/Instagram noticed in 2010. Meanwhile, in 2010, only 150 million of Facebook’s 500 million users accessed the site via mobile. Why? Facebook had been in at the start with the Facebook mobile app for iPhoneOS/iOS, frequently the number one downloaded app. But it was not a focus; one person (Joe Hewitt) created the app and in true Facebook fashion, really open source a whole app framework (Three20) that supported development of that single app. When Hewitt left the company in 2009, they needed to take a very different approach. Eventually they just bought Instagram and pretended they were cool all along.
A killer app sits in a precarious situation. It is an app that is so popular, it changes the value proposition of the platform it runs on; people went out and bought Apple ][ computers just so they could run VisiCalc. Musicians bought Acorn Archimedes so that they could run Sibelius. That is a problem for everybody involved. It is a problem for the makers of the killer app, because their platform vendor is not shifting enough kit for them to sell their software to all their customers. It is a problem for the platform vendor, because now they are not in control of the marketing for their product. The people who make the killer app want to port to different platforms, to satisfy latent demand. That is why you can get Sibelius for PC these days, and why Deluxe Paint was available for MS-DOS, Apple ][GS, and Atari ST. The people who make the platform want to diversify beyond the app’s customers, to regain control of the platform. That is why the marketing for the Mac is not all about how it is the latest thing from the people who gave you the opportunity to run VisiCalc. The people who make other apps want to make clones of the killer app, because it shows where the demand is. That is why you have used Excel, and you have not used VisiCalc. And the people who make other platforms want someone to make a clone of the killer app, so that customers choose their platform over the one with the killer app. That is the reason that IBM PC-compatible computers were briefly better marketed as “Lotus 1-2-3 compatible”; it showed that you could run the not-VisiCalc on the not-Apple ][.
The value proposition for software is entirely different in the 2020s than it was in the 20th century. Where Sibelius used to cost £795 to run on the £799 Acorn Archimedes, now you use the free software product MuseScore and do not (have to) pay anything; or you pay under half the previous, one-off price for a lifetime subscription to all future Sibelius releases (same number of currency units, but three decades of inflation later). Other than some die hards who believe in an innate superiority of native applications or of their favoured platform, you will not find much software that is not available for every popular desktop and mobile platform, either via the web or via web-like portable runtimes. No new killer app is going to arrive for any of these platforms, or for an upstart in those fields.
Why did the financial landscape change? Because the platform vendors could not afford to let a killer app take control of their marketing and sales pipelines. App stores exist so that the platform vendors get to choose what software gets sold, what price points and business models are available, and how the software gets described and marketed. No longer does a businessman walk into a computer store and ask for VisiCalc along with whatever box they need to make VisiCalc work; now they have to choose their general-purpose computer and then visit its souk to work out what they are allowed to do with it. Further, the platform vendors get to see what is doing well, and tailor their marketing appropriately—or build their own competing implementation.
Even if an app could break out of that restriction and build an identity that outshines its host platform, there is just no “moat” that defends any one platform from all of its competitors providing the same facilities. It used to be the case that switching computers was a huge deal: none of the software was compatible, none of the file formats were interchangeable, probably a floppy disk you formatted on one type of computer would not even get recognised on a different machine, even if it physically fit in the drive. That was not just true between manufacturers, but from different computers produced by the same company, too: try to run your Commodore VIC-20 software on a Commodore 64, Plus/4, CBM-II, or Amiga 1000. That is no longer true. All platforms have a web browser, meaning the unholy triumvirate of HTML5, CSS3, and JS is the ultimate portable runtime. A software company no longer has to choose a platform vendor and hope they can keep up with demand; they can reach everyone, whatever they run.
Might we get a killer app from the free software world? it is unlikely. When That is happened before, it is been in the narrow (but previously very lucrative) world of software for IT professionals: think GCC, LAMP stack, or Docker, it is pulled the rug out from under the proprietary alternatives, and the pricing floor with it, but has not led to people specifically buying into platforms because That is how you get to run GCC, LAMP stack, or Docker. Indeed it is one of the features of free software that you can modify the software to suit your needs, so if you are on Windows and you want the benefits of all of that free software, you port it. There used to be a whole company, Cygnus (Cygnus: Your GNU Support, now part of Red Hat, an IBM®™© brand), who did just that. Yes, you can buy a computer from System76 or the Raspberry Pi Foundation specifically because it runs Linux, but I am fine with Asahi on my Mac, my neighbour is fine using the Windows Subsystem for Linux, and my housemate just runs Audacity in Windows 11 on their NUC without questioning the value of their kernel. Free software does not have a moat by design, its purpose is to drain other platforms’ moats.
It is more likely that future killer apps will demonstrate the value of a new computing paradigm, and set up one of the platform vendors in that paradigm to be the largest supplier, for the couple of weeks it takes Claude Code to clone equivalent software for their competitors. There are precious few emerging paradigms though. You cannot count the “AI pin”/voice computing paradigm, because you can already do that on things that also have screens, so any compelling voice interaction software is already doable on mobile, desktop, web, and everywhere else. Besides, there are whole generations of humanity who are uncomfortable even having their phone ringer unmuted, who will not walk around talking to a computer like it is Majel Barrett Roddenberry standing behind the camera. Similarly, the whole LLM paradigm changes a lot of games, but not in any way that is exclusive to a single provider; whatever you do with Copilot, anyone else can do with an open weights Qwen model on their own computer (just maybe a little slower). Briefly, MoltBot/OpenClaw looked like being a killer app… but killing what, precisely? People bought Mac Minis, gaming laptops, workstations, they ran with Claude, ChatGPT, Gemini, there is no one “platform” that benefits in the market because of these tools.
Virtual Reality has been just around the corner for about as long as fusion power generation, and as much as it is found meaningful applications in many fields, still has not demonstrated the breakout utility that leads people in the mainstream to buy a headset just so that they can use that one, killer app. Similarly, augmented and mixed reality have even got real electronics that you have actually heard of selling consumer hardware, just not in meaningful quantities. As with VR, nobody has made a killer AR/MR app that makes people buy the hardware to use the software (if you are looking for app ideas, may I suggest a DuoLingo for sign language that tracks your hand movements, or an app for people with prosopagnosia that adds virtual “Hello, my name is” badges to people in contacts?).
Blockchain remains niche (and, for many, confusing: do I need to use a different currency just to run this software?), quantum computing is a mechanism rather than an interaction paradigm, so I think the only other direction from which we might see a killer app any time soon is the one that is furthest from the mainstream: smart dust. I just hope I did not use the phrase “killer app” in a hauntingly incorrect sense, there.
Cover photo by Museums Victoria on Unsplash.