I love Twitter. I use it every day. I’ve made a number of friends using the service, and often have interesting exchanges with an even larger number of colleagues and smart people. It has been essential to my career; it is hard to imagine doing my job without Twitter or some similar tool for connecting with the public.

But Twitter Inc has big problems. Its user growth dropped to to a trickle, with total user numbers still only at a fraction of Facebook’s. And no one knows how many of those users are robots.

Twitter brings in lots of revenue but it loses money. It looked around for a buyer, but no one was interested. User harassment is rife, causing a number of high-profile celebrities to quit the service.

Why is Twitter doing so badly, and how can it be fixed?

Part of the answer probably lies in the company’s culture. “Hatching Twitter”, a 2013 history of the company written by Nick Bilton, reveals that Twitter’s history has been one of power struggles, boardroom coups and strategic confusion. The main contest was between Jack Dorsey and Evan Williams, two of the service’s creators — the third founder, Noah Glass, was pushed out early. Dorsey, now the chief executive officer, eventually won the protracted power struggle, but the leadership turmoil left its mark on the corporate culture.

But after using the service for more than five years now, I’m convinced that the biggest problem is inherent to the technology itself. Short messages — what makes Twitter Twitter — are inherently conducive to insults, ill will and degraded discourse. Meanwhile, anonymity and the ability to message anyone on the site, although essential to Twitter’s nature, enable harassment.

Bilton’s history reveals that Dorsey and Williams did not just fight only over power and fame; they had different fundamental ideas of what Twitter ought to be. Dorsey conceived of the service as a way of posting personal status updates, while Williams thought of it as a way of reporting news. Glass, the forgotten co-founder, thought of it as a conversation club. In reality, it is all three of those. Celebrities mainly use the site in the way Dorsey intended, while journalists and academics use it more the way Williams envisioned. And Twitter has certainly helped me to connect with friends, meaning that Glass was probably on to something, too.

But there is a fourth important use of Twitter that none of the founders seems to have envisioned: Twitter is an ideal platform for being a jerk.

Unlike Facebook, Twitter is an anonymous service. What is more, unless you have blocked or muted someone, anyone can talk directly to anyone else on the site. You can tag other users in a tweet, and that other user cannot undo the tag, unlike on Facebook. This means that if you are even a moderately high-profile person — an actress, a journalist, a politician — you will constantly be subjected to a barrage of harassment by everyone who does not like who you are or what you have to say.

This includes not only people in your own circle, or even in your own country — it’s people anywhere in the world. Anti-Semitic trolls sitting in their basements in Hungary can threaten to send Jewish-American journalists to the ovens. Misogynistic teenagers in Australia can make rape threats against female journalists in Canada. There is even a popular comedy video series of celebrities and politicians reading mean tweets written about them.

Twitter acts as a force multiplier for evildoers. A recent study by the Anti-Defamation League found that most antisemitic harassment comes from only 1,600 accounts — many of them probably from outside the United States. But those 1,600 have managed to make life very difficult for many of Twitter’s Jewish users. Witness the attacks unleashed on writer Dana Schwartz after she criticised Donald Trump’s son-in-law.

Racism against black people is even more widespread. A flood of sexist and racist tweets recently drove Ghostbusters actress Leslie Jones off Twitter. And harassment of women is probably the most common of all.

After much initial reluctance, Twitter is cancelling more and more of the harassers’ accounts. But because it takes only minutes to generate a new pseudonym, they do not stay gone for long.

Yes, the dedicated harassers are just a few bad apples. But in any community or social network, there is some minimum number of bad apples required to spoil the whole applecart. And because of anonymity and unrestricted messaging, Twitter’s minimum number is exceptionally low.

But beyond active harassment and malfeasance, Twitter is simply conducive to hurt feelings. It is a lot easier to deliver an insult in 140 characters than to give a nuanced explanation of why you disagree with someone. The length restriction makes it easy to misinterpret things that other people say, and misinterpretation often leads to intolerance, aggression and closed-mindedness. Even reading my own tweets, it is easy to see how many of them could be misread as dismissive, arrogant and cruel.

I don’t know how to solve these problems. Many seem inherent to the technology, meaning that making Twitter a nicer place to be may require a deep rethink of the way the service works. But with user numbers plateauing and negative publicity increasing, this should be a top priority.

For the sake of a service I still love to use, I hope that Dorsey is able to come up with something.

• Noah Smith is an assistant professor of finance at Stony Brook University and a freelance writer for finance and business publications