From Google Apps: A Love Story:
Blame the consumerization of IT. BI-LOs users learned how to use Google Apps and similar Web applications in their personal lives. According to an internal company survey, 30% of employees already used Gmail at home and another 25% used a different Web-based e-mail service, like Windows Live Hotmail or Yahoo Mail. That familiarity translated into prior training — training the company didn’t have to pay for — and pre-existing affinity for the cloud.
In my eyes this is another good example of why there is a need for some kind of scaled down home version of Lotus Notes, with POP/IMAP support and possible connections to the most popular webmail providers, like Gmail, Hotmail and Yahoo. It must also be possible to combine all mail into one inbox, no matter the origin, and reply to mail making it look like it is sent from the correct service. So if I respond to a mail sent to my Gmail address, my reply will have my Gmail address as sender as default. Of course, I want to be able to change that before sending.