Zoho Mail integrates into their award winning Zoho CRM application. The integration of email is a very nice feature as it allows you to see what has been going on between your clients and team members without the need to CC email to each other.
Another Zoho product I have been testing under final beta is Zoho Campaigns. I have used many of these applications including Constant Contact, Mail Chimp, Active Contacts, Email Brian and more. Zoho Campaigns is by far the best newsletter tool I have used and with the bi-directional integration between the mailing lists and the contact in Zoho CRM it saves a great amount of time in managing your lists. So once Zoho Campaigns is available be sure to try it out as it is easy to use and 9/10 for functionality.
So check out Zoho EMail, Zoho CRM and the other Zoho products.
Cloud Solutions is a Zoho Alliance Partner and a Google Reseller.