This might have been because Saudi citizens, consumed by national indignation, took to their smartphones to show their support for the crown prince in his moment of difficulty: The disappearance and presumed murder of Jamal Khashoggi, a Washington Post columnist, under exceptionally grisly circumstances, has not been good for the international reputation of the royal family.
But it's equally possible that those hashtags were pushed by bots - fake, computerized accounts - as well as by paid, professional Internet trolls.
After President Donald Trump visited Riyadh in 2017, Marc Owen Jones, a Persian Gulf expert at the University of Exeter, tracked the accounts enthusiastically welcoming the U.S. president to Saudi Arabia. "Eighty to ninety percent of them were bots," he told me.
Despite its medieval aspects, Saudi Arabia is in this sense a thoroughly modern authoritarian state: Over the past several years, the Saudi government has fine-tuned a sophisticated information policy, one that bears a distinct resemblance to the sort used in other states that have also learned to use social media for social control.
As in Turkey, pro-regime trolls also gang up and organize online attacks against anyone who disagrees. Saud al-Qahtani, a media adviser to the crown prince with more than a million followers,encourages fellow citizens to add the names of dissidents to an online blacklist. Individual snooping also takes place on Facebook, where requests from "friends" may really be from the state's online spies, eager to get access to your information and your posts.
The Saudis aren't quite as good as the Russians at manipulating the Internet in other countries, though they are beginning to try. Qahtani has played around with pumping up anti-government sentiment in Qatar, Saudi Arabia's rival.
Over the past few days, Saudi accounts have also tried to spread smears against Khashoggi written in English, sometimes by pro-Trump writers and "conservative" American websites. They haven't managed to capture the story yet, but there is still time.
None of this is secret, not in Saudi Arabia, and not anywhere else. Censorship, in its 21st-century form, isn't carried out by old men in hidden offices, marking up newspaper articles with red ink. It is carried out by young men with mobile phones, working in the open, whose "patriotic" assaults on the "unpatriotic" are there for everyone to see.
It's also evolving constantly, as regimes observe one another's methods. On Wednesday, Twitter released data on thousands of recently banned Russian and Iranian accounts; according to the analyst Ben Nimmo, it appears that the latter were learning from the former.
The question is why Twitter isn't interested in their Saudi equivalent. Or, more to the point, why fake accounts and false identities are tolerated at all.
We aren't that far away from a time when it will become too dangerous for many people to risk the use of social media - and we've already reached the point where social media reveals very little of what people really think and believe. Maybe tens of thousands of Saudis really do want to pass on a #message of love for Mohammed bin Salman.
But if they don't, how would we know?