Instagram obeyed a Russian court order, while YouTube left it up.
Instagram has found itself dragged into a scandal about bribery, corruption and prostitution at the highest echelons of Russian society after banning an online exposé by a leading anti-Putin politician.
The social network yanked a 25-minute "investigation" fronted by Alexei Navalny and his Progress Party after a Russian court ruled in favour of the oligarch in the video, and ordered it to be removed.
YouTube, which also hosted the video, has taken a different approach, and has yet to remove the footage from the internet.
The video itself is a lengthy dissection by Navalny of evidence which he claims is proof of bribery between rich businessmen and senior policymakers in Moscow, improbably brought to light by a Russian escort with a penchant for sharing her glamorous escapades.
Scroll down to see exactly what it's about.
They can be seen interacting with staff, and posed outside for conveniently-placed TV news cameras from a pro-Putin channel.
She's appeared on Russian TV talking about her exploits, and has a book out as well, titled "Diary of How I Seduced a Billionaire."
She got more than one shot with him.
Here she is working out with Deripaska.
Here is a better shot of the pair together. Prikhodko is a deputy prime minister in Putin's cabinet.
He also highlights Prikhodko's large house outside Moscow, which he says is much too big for a lifelong civil servant to be able to afford and maintain.
He goes through a painstaking verification process, including flight records, photo analysis and cross-references with Rybka's book to identify the boat.
He says the photos support his claim that the two men were at sea together on the same boat with Rybka — potentially striking deals relating to the running of Russia's government.
Instagram complied, and removed posts from its service at the request of Russia's media regulator.
In a statement to CNBC, a spokesman said: "When governments believe that something on the internet violates their laws, they may contact companies and ask us to restrict access to that content.
"We review such requests carefully in light of local laws and where appropriate, we make it unavailable in the relevant country or territory."
Google, which runs YouTube, has so far not followed suit. They have also declined to comment.
Here's the entirety of video Instagram banned, and YouTube kept up. It's 25 minutes long and in Russian, though it does have English subtitles.