1) It reduces the workload on your server
2) It reduces the network traffic on your router, firewall, and any switches between the Internet and the server
3) Having a hosted spam filter eliminates downtime when you move offices, replace the server, or switch Internet service providers
4) Having a hosted spam filter allows you to move from in-house email to hosted (cloud) email with zero downtime
Here are three videos to show you why this is true. First, here's a quickie on how to set up your hosted spam filter.
How to Set Up a Hosted Spam Filter
Second, here's a video on moving your email server when you have a hosted spam filter in place.
Moving Your Email Server with a Hosted Spam Filter
Third, here's a video demonstrating the steps to move your email from in-house to out-house. Um . . . well out-of-house anyway.
Moving from In-House Exchange to Hosted Exchange Mailboxes
Feedback always welcome!