Copywriting is conveying information in a way that is meant to be intriguing or enticing. The job of a professional copywriter is writing the companies story, succinctly. Why they're important to the customer. If a company can reliably do this in different formats, they will connect better with their audience, driving sales up.
Copywriting can be in the form of a tagline or slogan like "I'm lovin' it", or go into more detail with text like blog post's. This is an example of a post with good copywriting.
My formula for good copywriting:
(thought-provoking connections to bigger concepts + displaying and answering a need) - unnecessary text = good copywriting
Benchmade Knives makes some great products. This is the first thing you see when you click on their website.
At the moment, Benchmade is promoting a new product. But if they weren't, some good copywriting would be needed to fill that space, while explaining Benchmades importance. This is what I would say:
Go to where performance and reliability meet, we'll be waiting for you.
We equip those who do what is difficult and give them the edge to do it efficiently (literally).
Imagine that in front of a high-def picture of using a Benchmade knife for a hard task, or the Benchmade team. That would be good copywriting.