From the article: "What's motivating organizations to deploy MPLS?"
When we drilled down into the survey data, we found a strong relationship between the deployment of VoIP and the deployment of MPLS. In particular, the vast majority of companies that are either making their initial deployment of VoIP or expanding their VoIP deployment are also planning on expanding their QoS policies. The vast majority of these companies expect to expand their QoS policies by implementing MPLS.
Interesting correlation between VoIP and MPLS.