Message Bus' principal objective is to improve email delivery. In addition to building relationships with ISPs and educating its clients about deliverability, Message Bus is built around a cloud-based infrastructure that it believes is a unique advantage for deliverability. Instead of relying on a single cloud service provider, its Global Delivery Network deploys on a number of different cloud services (currently Joyent, Amazon Web Services and Rackspace), allowing the company to move workloads across different infrastructures as needed.