As perhaps the clearest indication that open source has "arrived," take a look at the company it keeps. For example, today SpringSource announced that it has been elected to the Java Community Process Executive Committee. Good for SpringSource, right? It now gets a seat at the Java table and can help to improve enterprise Java.
But this isn't the real news. No, the real news is that open-source SpringSource joins SAP, Ericsson, Nokia, Philips, and IBM on the JCP Executive Committee.
It's similar to to open-source content management and collaboration vendor, Alfresco, being chosen to participate in the CMIS standards body, along with IBM, EMC Documentum, Microsoft, OpenText, Oracle, and SAP.
Little SpringSource. Little Alfresco. Big open source.
Open source has arrived. Just ask the incumbent vendors who can no longer hold back the tide, but are under increasing pressure to allow open-source vendors and communities to break open their cabals and participate in setting industry standards and technology direction.
It's about time.
Disclosure: I am an Alfresco employee.