I think that `mvn install` is one the *most popular* default we can propose. This command will traverse into all of the sub-projects (a.k.a sub-modules) running all the [maven lifecycle steps](http://maven.apache.org/guides/introduction/introduction-to-the-lifecycle.html) (except `deploy`). With `install`, built packages are installed into the local repository, for use as a dependency in other projects locally, which can be required in multi-module project for instance.

That said, `mvn verify` could also be a good default, and maybe less confusing. It would be cool to get some more eyes and thoughts on this point...