"A fantasy world full of WoW-like fantasy"
Possibly you have in front of you one of the best role-playing video games in web browsers (through a plugin) that have ever existed and that, humbly, only requires a graphical plugin.
This is Free Realms, is a massive online role-playing game with graphics very similar to the more than well-known Blizzard video game, World of Warcraft. Indeed, with a similar video rendering and a surround sound very faithful to its graphics.
Travel the vast world interacting with other players, killing monsters or playing mini-games. Unlike other games of the style, Free Realms is rather peaceful and social, leaving the fights in a clear background.
The best part is that without leaving the browser you can record your games and upload them to Youtube directly from the website of the game, more comfortable impossible.