Google Apps for Business

In my opinion, Google is the best email host at the moment. If your email address is at GMAIL.COM, then you have Google hosting the email for this account. Moreover, if you want to get an email account with a custom domain like yourcompany.com and want Google to host the email for this domain, then you need to pay Google some money for its Google Apps for Business. Remember, Google only hosts the email service for the domain, not the domain name itself and its DNS service. These two services can be hosted by Google as well if you want, but not necessary a requirement for Google to host the email aspect of the domain.

Google Apps for Business has 2 plans: One with Vault and one without Vault.

The one without Vault is $5 per email address per month with prorate or $50/year. With Vault, add an extra $5 to each account per month. If you choose Apps without Vault, there is no retention of emails that are deleted and the Trash is emptied. By contrast, with Vault, the deleted emails are retained forever as long as you continue to pay Google the extra $5 per account per month to use it. The emails in Vault does not count against the quota in the inbox. Google will also help you with any ediscovery process if required by the courts, certifying that these deleted emails' timestamps and chronology have not been modified. In short, Vault is industry PCI compliant. 

Customers of legacy Postini email retention service will be transitioned starting 2014 to Vault without paying the extra $5. As to how long this generous offer will be, it is unknown. This includes the limited time Postini services such as those only retain the email for 3 months for example. With Vault, the limited retention period is expanded indefinitely. Again, Google may not offer this generous entitlement for grandfathered accounts for long.

Each account gets 30GB of storage that is shared between the various services such as mail, Picassa, Docs, and so forth. If you need more storage, you can buy it. Vault storage is indefinite and is not part of the initial 30GB quota.

If you have multiple accounts (multiple email addresses) for the domain with Vault, each account can have its own Vault license. This means for certain accounts that are more critical, you can assign a Vault license to it to enjoy the retention benefit. For the non-critical account within the same domain, you can use it without Vault. Vault licenses are transferable. Once transferred, the retained email associated with that Vault license is deleted forever. 

If you miss a payment for the month, there is a 30-day grace period where all functions still work. For the next 30 days, the whole domain or any specific unpaid accounts are put on suspension without deletion. After 30 days of suspension, this account or domain will be deleted forever. The point is make sure you pay Google on a timely basis. It goes without saying. It's a business, not a charity.