Mailchimp is an email newsletter and email marketing tool - free up to 2,000 list subscribers - and allows autoresponders to be set up. It also offers great analytics on views, clickthroughs, etc. and integrates with Highrise CRM and a variety of other tools. Great email template designs, too.
Measure influence - in this context, a user's ability to move content across the social web. Measures FB, Twitter, Linkedin and Google+ (with ither networks providing limited influence on scores)
Kred - Measures influence based on the propensity of others to share your content and mention you, as well as your outgoing engagement (Mentions and RT's for Twitter, for example)