Keep Your Friends Close - A free e-book about maximizing Customer Lifetime Value
Customer Feedback Portal - Ask customers what you should build next
Receiptful - Receipts that increase CLTV. Exclusive (early access to PH)
Feedback Tools - Curated directory of tools for getting all the feedback
Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
Feedback Fish - Collect feedback & make your customers happy.