Paris' subway and local train lines each have a Twitter account, and they are the only reliable source of information regarding outages. Phone apps (at least three official ones with different data sources!) and websites can be outdated. Displays in station too (though less often), have outages of their own, and (rarely) even incorrect updates.

A few recent examples: https://finance.yahoo.com/markets/currencies/articles/bessen... https://theprint.in/world/us-military-says-it-completed-late... https://www.reuters.com/technology/brad-lightcap-leaving-ope...

It’s still the go-to platform for public figures to broadcast unfortunately, so if you want to verify the original comments you need an alternate frontend or an X account.

Last time my city had a water cutoff due to a broken main, the city hall posted on Twitter (and I think Facebook?) where and when to queue for drinking water sooner and much more often than on any other channels, their own website included.

They don't use Twitter, but my university exclusively uses Facebook for news and relevant announcements like scholarships, days off due to weather, etc. they won't even use their official webpage but for posting the official calendar...

Any big information fan out is pretty useful for JP twitter. Like yes, we’ll get notifications for flooding / earthquake and etc., but if you want up to date, on the ground videos and etc. it’s pretty useful. Not even talking about the train line scenarios as other commentators mentioned.

There’s a system that is not replicable unless you have majority of the population on the same social media.

I don't know about crucial, but a recent amber alert went out last week. It contained a bit.ly link to the CHP's Twitter page and I couldn't see the information. I clicked on it because the alert was from my town, but light on the details.

Surely a public post on a CHP website would have gotten the job done better.

I don't know if it is still the case, but when I was writing some Wikipedia articles I discovered the British monarchy seemed to use Twitter exclusively for some purposes.

Irish rail posts about train delays exclusively on Twitter