This is the first time I've heard of the Jobs to Be Done process, essentially a take on understanding the why behind your customers 'hiring' your product or service - what job does it do? In this instance it frames how they optimize their landing page design to appeal to the 'jobs to be done' perspective. This is a different approach vs persona based marketing which focuses on the 'who' and given the phenomenal growth Intercom has seen recently would suggest its worth investigating by all product focused companies out there.
The first thing you should do before writing a single line of copy is get an intimate understanding of the job people are hiring your product for. Know what creates demand for it and what people are searching for when looking for a product to hire for that job.