He took two data sources (LinkedIn and LinkedIn data hack) and combined them to get first, last, email, linkedin profile ID. Imagine a spammer having millions of active email addresses with first/last.

> Imagine a spammer having millions of active email addresses with first/last.

Don't they already? There have been SOOO many breaches in this area that I rather doubt there are many active emails that don't have some publicly available dataset linking them to first and last names. The valuable thing here is linking that data to the LinkedIn profile ID.