Last month Jack Dorsey was standing in Addis Ababa Bole International Airport in Ethiopia, which, according to reviews, has “insipid food choices” and a “pathetic duty free,” when he tweeted a major announcement: “Sad to be leaving the continent…for now. Africa will define the future (especially the bitcoin one!). Not sure where yet, but I’ll be living here for 3-6 months mid 2020.” At Twitter and Square, the two companies Dorsey runs almost 9,000 miles away, Dorsey’s employees were as perplexed as everyone else. According to people close to Twitter, no all-hands had been called to explain that their boss was planning to spend a good chunk of next year overseas. There was no explanation—just the tweet.

Had someone like Mark Zuckerberg or Tim Cook or even off-the-cuff king Elon Musk sent a similar tweet, their companies’ respective stocks would have plummeted, lobbing a few billion dollars off their valuation; the CEO of a major public company moving oversees without much explanation isn’t normal. But at Twitter, the markets barely registered the so-called announcement. That’s because Twitter is not like any other public company, and its investors are as perplexed as ever about how to judge its worth. Its valuation doesn’t match its revenue. Its user numbers don’t match its influence. And, unlike Apple or Facebook, Wall Street still isn’t sure if Twitter’s CEO, Dorsey, is one of the metrics they should use to decide that value.

I’ve long since given up predicting the market capitalization of Silicon Valley companies. There are simply too many random factors, like Russian interference, tens of millions of “users” turning out to be bots, or, more often than not, the firing of a big-shot CEO. Uber, I once believed, could be worth $100 billion, or nothing. (It’s now bobbing somewhere in between.) I once assumed the scandal surrounding Facebook and Russia would chop off a good quarter of the social network’s value, and while it did fall by a hundred billion dollars or so after the Cambridge Analytica news broke, Facebook is now worth more than half-a-trillion dollars, and continues to grow. As for Twitter, a company I’ve covered for more than a decade, while the company’s value has gone up and down like a yoyo, my predictions of where it might be at any given moment have always been off by several quarters, if not years. In 2015, for example, as the usual chaos was gripping the Twitter boardroom and Dorsey had taken over for the third time (his second as CEO), I guessed that the social network’s stock would fall dramatically. While I was right for a while, Twitter’s value is now in the same ballpark as when Dorsey returned, in part thanks to the Tweeter-in-Chief.

That’s not necessarily a good thing. Half a dozen people I’ve spoken with who once worked for Twitter or who are current investors have voiced concerns about how long the company can continue on its trajectory of remaining stagnant as a platform with an absentee CEO, and whether it can reverse course on its flattening ad revenue, which increased by a negligible 8 percent this past quarter. (For comparison’s sake, Facebook’s increased by 28 percent. An ex executive who left Twitter after Dorsey returned to the company said the only reason Twitter is still around is because “it’s like the monster from Stranger Things that just can’t be killed and comes back every season.” (The executive left the company precisely because they saw the future wherein ad revenue would slow and, eventually, fall.) Another former senior manager described Twitter’s business model as “a house of cards waiting for the right gust of wind.” And one current investor noted that the stock this week was lower than it was when Dorsey came back almost four and a half years ago. User growth hasn’t fared much better. Twitter now has more than 2 billion users less than Facebook. In America alone, only 30 million people use Twitter daily.