One of the major weaknesses of Salesforce.com is email integration. One of the major weaknesses of other email integration or email logging services is that they cannot match email to Contacts Only. Match My Email solved this issue for a current customer and released Contact Only matching in the latest version. Match My Email Contact Only matches both inbound and outbound email with Salesforce.com.
Here is a quote from a review on the Salesforce.com AppExchange,”The only issue I have is that VCS Smart Email cannot log inbound and outbound correspondence directly under the relevant Salesforce.com contact.”