While I support this, I do think that it has its place in academic or classic literature — not popular fiction and certainly not extremely popular fiction. Why? Ask any Harry Potter fan! I may be admitting too much here, but when book seven of the wildly popular series was released to bookstores, I raced to get a copy. Avoiding Facebook and Twitter was hard enough, and I'm a fast reader! If a book was spoiled via Twitter (however unintentionally) I'd be crushed.
The bottom line: the capability is awesome, just please use it responsibly!