WTF is Roblox?

MightyUnclean

I just saw an article on MOP that says Roblox has like 100 billion players or something ridiculous.  Why have I never heard of it?  Why isn't it discussed on here?  Is it mainly for kids like the description here says, or do adults play, too?  For that matter, what, exactly, is it?  Some sort of hybrid between a full-fledged MMORPG (description says MMOG) and a platform that allows players to create their own games?  I'm so confused.