Unlike announced in my previous post this one is neither soon nor on a surprise topic. It is about a general aspect of Android that is, to my opinion, very powerful but often under utilized.
Android apps are not monolithic but rather a collection of components of different kinds. I suspect android took inspiration from the concept of midlet suites in j2me and believe it expanded on that quite well.
These components (except for provider) can be exposed through intent filters in the package’s manifest and can be used by other components in different packages. This allows apps to accomplish tasks together which a single app could never do.