Does Rosetta Stone Work?

Well...  Yes and no.  It really depends on how you work with it.

I personally object Rosetta Stone because, for one thing, it's overpriced.  I have actually tried a friend's copy of Rosetta Stone and I simply have no need for it.  A full package costs $400, with the online tutor an extra $240/year.  Why pay more when I have resources that already do the same thing for less money or even for free?  (iKnow! for vocab and dictation, EduFire for the tutor, Livemocha)

Another thing.  There is still more to learning a language than sitting at your computer.  The brain is like a muscle.  It needs exercise.  Use what you learned with Rosetta Stone to keep it in your head.  Watch movies/youtube, read books, listen to music, make friends who speak the language.  In my five years of experience, immersion requires more time and effort than what Rosetta Stone touts.

Am I saying that Rosetta Stone is a bad resource that nobody should try?  No.  Far from it.  The software provides the basic needs for learning a language like flashcards, dictation exercises, reading and listening.  It can be beneficial for a person's ability to learn.  if you can afford it and it seems to work for you, then go right ahead.  But try to combine it with another resource.  Maybe fill the gap by watching movies, and communicating with native speakers on Skype or Lang8.

Language learning works like a multiplayer game.  By this, I mean there are multiple combinations of classes and perks to choose from.  My preferences involve watching Japanese movies with Japanese subtitles combined with an iPod dictionary. I have Japanese friends for conversation, and I use flashcards with mnemonics for vocab.  Another person may choose to buy Rosetta Stone and combine it with movies and social interaction with a tutor on Edufire or maybe a friend on skype.

Overall, when it comes to language learning, to each his own.  I may not be a huge fan of Rosetta Stone, but if it works for you, I say do it.  Just remember that no one resource by itself is perfect.