Pointofmail.com - Know who, when and where read, clicked and forwarded your email.
Salesflare - Simply powerful CRM. Automates your data to build better relationships and make more sales.
ReadNotify - ReadNotify enables the user to know when email is sent and the reciever reads the email.
17hats - The all-in-one business system for entrepreneurs.
MailChimp - MailChimp is the best way to design, send, and share email newsletters.
LinkPoint Connect - LinkPoint Connect: Desktop Edition for Salesforce links the work you do in your email to the records you need to update in the CRM.