There are so many options to consider for your email solutions that require consideration of how you want to manage them, where you want to host them (locally on your servers or in the cloud), how you choose to protect them, where you would like to store them and if you want to securely archive them.
Traditionally many businesses hosted their own emails using their own premises based servers or domain and email provider.
Nowadays it’s claimed that over 200 billion emails are sent every single day, which means about 20 million were sent while you read this sentence.
With so many emails now being sent and received the needs have significantly shifted to consider not only how they’re managed but security, storage and business continuity.

http://mashable.com/2012/11/27/email-stats-infographic/#NHxZuZ_U2Gq3