In technology, ecosystem is a big thing. I remember, 10 years ago, while looking for a device/service, one would go for whatever is best in that category. This approach doesn’t work that well anymore. These days it makes sense for a person to stick to an ecosystem and use products/services mostly in that ecosystem, otherwise things get messy. This is because each of the three big companies want the users of their services to use their products exclusively and as a result, don’t support cross-platform compatibility very well.
Here’s an overview of the services/products offered by the Big-three. For those who are curious, I am firmly planted in the Microsoft ecosystem.