On Friday, Ukrainian leaders pleaded with Apple, Meta and Google to restrict their services inside Russia. Then Google and Meta, which owns Facebook, barred Russian state-run media from selling ads on their platforms. Sundar Pichai, Google’s chief executive, also spoke with top European Union officials over how to counter Russian disinformation.

At the same time, Telegram, a widely used messaging app in Russia and Ukraine, threatened to shut down channels related to the war because of rampant misinformation. And on Monday, Twitter said it would label all posts containing links to Russian state-affiliated media outlets, and Meta said it would restrict access to some of those outlets across the European Union to ward off war propaganda.

For many of the companies, including Facebook, Google, Twitter, the war is an opportunity to rehabilitate their reputations after facing questions in recent years over privacy, market dominance and how they spread toxic and divisive content. They have a chance to show they can use their technology for good in a way not seen since the Arab Spring in 2011, when social media connected activists and was cheered as an instrument for democracy.