We all know that the locket found in the cave by Dumbledore and Harry was a fake, replaced by the mysterious R.A.B. Where the real locket lies now... I have no idea. I was confused by this at the end of the book because I was unsure whether we could trust this mystery person to have been able to destroy the locket or whether we should assume that it is still out there somewhere. Harry seems to believe he has yet to find it... which is proven by his mantra of
the locket... the cup... the snake... something of gryffindor's or ravenclaw's... I guess we will find the answer to this in the last book.
I think that the locket either lies destroyed or with an accomplice of R.A.B. I seriously do not believe that R.A.B. would be able to complete the task alone. If Dumbledore himself needed to be force fed the liquid, then I doubt any other wizard or witch would be able to successfully retrieve the locket. So this could mean that some other person out in the world knows about Voldemort's horcruxes and may be attempting to find the remaining 4.
I guess I'm also just wondering how in the world Harry is supposed to find the rest of the horcruxes. It seems so improbable to me for him to do so much in so little time. But I guess when there's a will, there's a way. His revenge against Snape and Voldemort may drive him to extremes that may ultimately save the world.
Does this make any sense?