At first I thought, wow! You don't see a company that big up and change cloud providers very often!

Then I remembered Microsoft bought them (3 years ago now).

Yes...seems to be completely a political decision rather than a technical one..also it reminded me of gitlab's decision to move out of Azure...

Vertical integration more than political. Like Samsung phones using Samsung DRAM and storage.

It isn't a 'change of cloud providers' as such because, a couple of years ago at least, LinkedIn was running its own server estate in a number of global, regional data centres.

Happens alot lately. Beside own subsidiaries, Microsoft creates "partnerships" and all of those "partners" sooner or later migrate to Azure.

Ofcourse its one way to beta-test your services. Hopefully it will increase the quality of the service.

I wonder if they will make a better job of it than they did moving Hotmail to their own platform.

As an Azure customer, I have hopes that having a bigger fish in the pond would help improve reliability and availability, but those would likely happen for services that are already reliable.

What do they currently use?

Their own data centers.

Oracle! Ha, got you.