OK, you caught me :shifty:
There used to be the WordPress.com Stats plugin.
WordPress.com stats has merged into Jetpack. Please use Jetpack instead of this plugin.
WordPress.com stats has merged into Jetpack and all future upgrades to WordPress.com Stats will only be available in Jetpack. Jetpack connects your blog to the WordPress.com cloud, enabling awesome features. Get Jetpack now!
There are many plugins and services that provide statistics, but data can be overwhelming. WordPress.com Stats makes the most popular metrics easy to understand through a clear and attractive interface.
your idea of what "most popular metrics" are might differ.
These may or may not be good enough for you http://en.support.wordpress.com/stats/
And just because WordPress is closely tied to Automattic and shows both Akismet and Jetpack in the AdminCP doesn't really make them "core", though I imagine they're well integrated, or at least would hope so.