Many, if not most, companies are either moving services to the cloud, or at the very least discussing this internally. Moving your email to the cloud might have many benefits. The most significant benefit is probably cutting costs by not having to allocate resources on maintaining these servers.
If you are a Microsoft-shop and are currently running an on-site deployment of Microsoft Exchange, you might be tempted to switching to Microsoft’s (fairly) new BPOS service. The pricing for BPOS is a bit higher than Google Apps, with a price-tag at $10/user/month (compared to Google Apps Premium at $50/year), but if you want to stay with Exchange you might consider this cheap.
Migrating your existing users to BPOS is a pretty straight forward process. Everything will probably work out just fine until the day you realize that PBOS doesn’t fit your company’s need anymore. Yep, that’s right. You’re stuck. BPOS doesn’t even allow you to access the mailboxes though IMAP or any other standardized protocol to extract the data.
The bottom line is that you should really think about both the migration to and from any email system. If you want to switch to a hosted Exchange system, don’t go for BPOS. Instead, chose an Exchange provider that doesn’t try to lock you in.
Our database includes plenty of Exchange providers that have IMAP enabled, which allows you to move your data to a different provider whenever you decide to.

Great blog. Many blogs like this cover subjects that aren’t found in magazines. I don’t know how we got on 12 years ago with just print media.