I had a group of friends I roleplay'd with on WCIII. When we first started, the roleplay followed the stories of a handful of highschool students gifted with supernatural powers. Eventually, it evolved into an expansive universe filled with gods, alien invasions, demon incursions, an X-COM-esque group of supernatural beings, and hundreds of main characters all living their lives in this master universe. Eventually we had to reboot the world because the main villain died (along with some of the original characters) and took the Titans (from Greek mythology) down with him. We had everything from timeless knights to power armored space travels and angels, demons, vampires, and an entire civilization based on ancient Rome living on Mars. all in a semi-believable universe of total craziness, where pretty much anything that you could imagine, happened.

The only reason it worked was because the six of us were pretty loyal friends, who loved to Roleplay and enjoyed each other's company. I'd not sure it would have lasted anywhere near as long if it we had just been a bunch of random strangers.