All the Half Blood Prince rumors that ain't true
A few rumours about Harry Potter and the Half Blood
No time travel for Dumbledore
Nope, says JK Rowling, author. The wizard Dumbledore is not from the future. He is nto a relative from the future, or even Ron Weasley from the future. He is here, and now. No time travel, no science fiction in Half Blood Prince. Sorry!
No heavy emotional triangle between Harry, Ron and Hermione
There has definitely been some interest between Ron and Hermione - okay, not so sure about her, but Ron has a thing for her. But that is not going to be a major part of Hlaf Blood Prince. Oh sure, there could be some developments, but that's about it.
The number of chapters
There were rumous that there would be 38 chapters in Half Blood Prince. Not so. Fewer. Not 38. Pages, on the other hand, could be higher!
Harry Potter will not end with Book Seven
Nope, it will. The final book is already done, and ready - though we can probably expect it only after another year. So Book seven will be the final one.