During one of my bouts of insomnia, I was reading through some very old threads in the Leaky Lounge and I came upon one from February that was asking for predictions about the release date of book 7. I
made a bemused guess that it would probably come out in Summer 2007 and gave the date of 07-07-07. Now that HBP has beat us all over the head with the importance of the number 7 (as if we couldn't have guessed at that already), I'm even more convinced that 07-07-07 is probably a target date that Jo has in mind while writing.
Don't ask me why I'm even writing all this now. It's 3:38 AM and I'm trying my hardest to avoid packing. And it's working.