[inglor]

> What do they lead aside from search, ads, and mobile OS?

Browser, email, self-driving cars. Lots of other stuff too...

[joshuapants]

> Browser

Leading in memory usage perhaps

[neumino]

Leading in security.

[yellowapple]

Nah, Internet Explorer takes the crown there.

[icebraining]

Leading in self-driving cars is debatable. They surely have the most visibility, but some car manufacturers and academic institutions like VisLab also have some impressive prototypes, e.g.: https://www.youtube.com/watch?v=xNcyuApIlFw (the autonomous car is the one in front)