The hypergrid is a bunch of virtual worlds — around 300, by last count — that allow avatars to travel between them.
Any OpenSim-based world that is connected to the Internet can be on the hypergrid, simply by enabling that setting when it is configured.
Test-site stub. The full text of this page will be migrated from the live site: https://www.hypergridbusiness.com/faq/how-to-hypergrid/