tl;dr:
1. Have a high LTV:CAC ratio (what???)
2. Have high viral co-efficient. (okay.)
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LTV = Loan to value, a ratio of the outstanding debt on a property to the market value of that property. (or is it "Lifetime value" of a customer?)
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CAC = Customer acquisition cost is the resource a business needs to allocate in order to acquire an additional customer.
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And, oh yeah, just "be viral".