I just spent a glorious while in the Cavern and other places in the Uru universe. It is amazing and awesome to have Myst Online back. There is something so instantly worthy about the experience. The imagery/graphics are really gorgeous, and the music is sometimes achingly lovely.
It is a place I have spent many hours in, so tonight felt like riding the ol' bicycle - I collected a bunch of Relto pages (and yes, the Island one was hanging around in its usual spot), kicked a fire marble or two, did NOT dance on the Heek table, got my KI, ran the Cleft puzzle, and posed for a group photo in the Uru Obsession Bevin.
None of that makes much sense to most of you, but luckily for you, Uru is currently free and open source. The servers are still pretty limited and laggy, but it's still pretty awesome that they're making this experience happen at all.
You can start here:
http://mystonline.com/en/play/ I can answer questions, and the community that has been playing Uru since 2003 or so is an extremely helpful and gorgeous bunch of people.
The Cavern awaits. Fiendish puzzles. Go.