The Grid is somewhat like the internet in the early 21st century. Cydonia explorers stole as much information from the existing Earth data banks to piece together the first grid to store that knowledge. Rumor has it Jacyll Kaen had a major role in the invention of The Grid, you know, before he lost his mind.
Over time it reached beyond Earth and evolved into a galactic power house of entertainment and communication. You can just about do anything that you put your mind to it (Like leisurely space travel)!