There seems to be a trend toward outsourcing email to third-party service providers. It makes sense. Let's face it. Email has gotten really complex and you are likely to have built up a small army to service your company's needs. Outsourcing would be a no-brainer were it not for compliance issues. In a sense, the issues with email service providers are the same as with any service provider. You need compliance guarantees. Beyond that you need proof that they are archiving in compliant fashion. That should be your number one concern. Many are watching Google, which recently bought Postini, an email service provider. You would have to think it will have to add compliance features to make a serious run at big enterprises. So far, the issue has not been addressed in full.

For more:
- here's an article from NorthJersey.com