Screets - Screets is self hosted Live Chat!

Froged - One click solution providing easy-to-use marketing, sales and support services to turn website visitors into happy customers.

Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.

Keep Your Friends Close - A free e-book about maximizing Customer Lifetime Value

Open Web Analytics - Open Web Analytics - Web Analytics – Open Source Web Analytics Framework

Intercom on Customer Engagement - A book on how to create messages that drive engagement