Sonar & Maven

Sonar is a very nice tool. One of the few that will show how your metrics evolve over time.
But the cooperation between Sonar and Maven isn't that obvious:

• There is a misleading org.codehaus.sonar version1.8 that evolved to org.codehaus.mojo version 1.0-beta-1. Internet being what it is, you still find documentation referring to the deprecated version.
• There is an interesting debate about what should be in Sonar and what should be in Maven.