Another important consideration when deciding whether to outsource your e-mail is performance. E-mail in the cloud will most likely mean higher latency and slower transfer speeds for messages that travel within a company's internal network. What's more, as IP links from individual desktops within an organization multiply, bottlenecks in the networking equipment under IT's care could begin to develop. In many companies, e-mail serves as a catchall collaboration and file-sharing tool, and one way to improve performance in the face of a hosted e-mail migration is to encourage and ease the use of local file shares for large attachments exchanged within a campus.Another interesting hybrid approach that retains the virtues of hosted e-mail without sacrificing the performance benefits of on-premises e-mail is the tack taken by Azaleos, in which the company delivers remotely managed Microsoft Exchange appliances to customer sites.
Hosted e-mail services do tend to locate spam filtering facilities up in the cloud, which can cut down on the amount of mail-based traffic flowing into your network. However, in a good example of a hybrid hosted/on-premises approach, these same sorts of hosted filtering services can be teamed with otherwise on-premises e-mail services.