There are two types of leads that make up your pipeline – inbound and outbound – and the way you treat them should be different.
Generating leads is a way to build pipeline. Inbound leads are when the prospect comes directly to you for example when they fill out a "Contact Us" form, request pricing or a demo, or download content from your website – such as whitepapers or eBooks.
Outbound leads are when you reach out to a prospect in order to actively create your own pipeline. This is what tends to be referred to as cold-calling.
When building your pipeline through outbound you need to pitch your prospects on why your product or solution is a good fit for them, and why they should take the time to meet you or learn more.