“More companies are making the choice to move from their own on-premises exchange servers for email to hosted cloud based mail solutions. The market leader by a wide margin for this service is Office 365.
There are multiple benefits to cloud based mail solutions vs the local office exchange server; for a significantly lower initial investment you are able to provide greater redundancy and accessibility. Office 365 and other providers will also offer various integrated mail backup and antispam facilities.
When migrating to a cloud-based platform it is wise to first rationalise your mailboxes and perform a prune of mailboxes and mail data. Remember; Cloud-based mail services are charged on a per mailbox basis so you want to avoid adding mailboxes that are not required. Smart use of mailbox aliases and distribution groups can help with this. (Office 365 does not charge for aliases or distribution groups; however, this is not always the case with other providers)
The quantity of data you will need to upload to the cloud and the rate at which you can upload it. This will determine which method of migration you will wish to perform. A smaller database or a faster internet connection will allow the use of a third party tool for a simple mailbox to mailbox import over the course of a few days; whereas larger databases may necessitate active directory integration to allow synchronisation of email of a course of weeks. Office 365 offers a generous 50 Gigabyte of storage for each user’s mailbox.”