Tom Sullivan writes about UML 2.0 spec.
Looks like they are adding more riguor and fine details to the already-too-detailed language. In years of informally using UML I've never seen people actually being successfull of using the language as it was originally intended - formal definition of a software system. Apart informal brainstorming, another great use of UML is communicating design patterns.
Where I've seen UML fall flat is when people attempt to capture an entire architecture in a static UML model. Such model will inevitabely go obsolete and out of data with the code.
IMHO what developers miss is some real practical tools that use UML beyound its informal whiteboard usage. It would be great to have a lightweight way to link the code and the UML model. Once the two are linked, ether the code or the model can be edited.