InstAddr - Disposable email address application.
Boomerang for Outlook - Boomerang for Outlook offers email productivity tools to track, schedule and send mails at the right time.
Horde - Horde Groupware is a free, enterprise ready, browser based collaboration suite.
Covideo - Covideo is a Video Email Platform for Businesses that enables companies to communicate quickly and effectively with their customers.
Mailo - Mailo is an email client where you can send and receive emails to and from anyone with an email address.
Outlook4Gmail - Outlook4Gmail provides easy synchronization of your Outlook and Google accounts