Google Drive Stacks
What is a Google Drive Stack? Google Drive is a free and paid product that Google offers in order to support people and businesses with products like Documents, Slides, Forms, and much more. All of those documents are then stored in the user's Google Drive. Users can then publically (or privately) share each or all of the contents of a Googe Drive, and best of all, they can even be indexed and ranked in Google search.
From an SEO perspective, using Google Drive Stacks leverages the power of the Google domain and trust in order to promote your website both from an increased rankings perspective, as well as from having additional ranking properties in the search results.
You can use stacks to test new markets, test competition, or get the rankings boost without resorting to PBN's in most markets assuming your on page optimization was done well.