What are some alternatives?
CleanEmail - CleanEmail is an online service that empowers you to take control of your mailbox.
MailClark - The Slack bot for external communications
Email Signature Rescue - Create, manage and deploy beautiful customized HTML signatures in any email client.
DuoCircle - DuoCircle provides enterprise spam filtering and email management solutions.
MessageOne - MessageOne offers email management solutions such as EMS and AlertFind for archiving, e-discovery, security and notification services.
Freshdesk - Freshdesk is a cloud-based customer support software that lets you support customers through traditional channels like phone and email, social channels like Facebook and Twitter, and your own branded community