JK Rowling has a new... something. We don't know exactly what it is, just yet -- we'll find out at 11am tomorrow -- but it's already started getting fans of the Harry Potter author stirred up .
The one thing we know for sure is that Pottermore isn't a new book -- that's the only steer that's been given by Rowling's people. Speculation is rife as to what it might be -- the long-awaited Potter universe encyclopedia, for example, possibly a roleplaying game played across social media, or some other treat sure to delight millions of fans.
That it isn't a new book is something that catches the mainstream out a bit. If not a book, or a film, then what is it? Those kind of things are easy to write about and understand, or present to readers you don't think are as clever as you are... but a socially networked roleplaying experience? That's something that's not quite so tangible, so easy to describe, so straightforward to boil down into its component parts. Which is probably for the best: after the Potter books, it makes sense for Rowling to bring her talents to something innovative rather than something expected.
Pottermore's holding page  doesn't reveal much, with two owls staring out at the viewer and Rowling's signature promising something "coming soon"... and that's about it. The 25 other owls sitting in branches at Rowling's YouTube page , which appears when you click on the holding page, aren't giving the game away either.
With such little information to go on, every single detail is being analysed and re-analysed. Are the numbers, 0.09 of 1.13, of any significance, for example? One poster at the Potter forum Chamber of Secrets  attempts to decode the numbers on the page, saying: "Date is 4th February, which is when Septimius Severus died. Plus, the timer says 0:09/1:13 -- and 9/1, or January 9th, is Severus Snape's birthday. Also, in some areas, 9/1 means 1 September, the first day of school at Hogwarts. The year of 2013 could indicate the beginning of the next generation at school."
It could mean that. It could mean nothing, of course, but the delay from the June 15 announcement that there would be an announcement has left a neat little void for the excitement and speculation to fill -- exactly the kind of thing that has set forums and online communities buzzing about what it could be, and where Rowling is going to take her millions of fans next.
The uncertainty is tantalising. One Potter expert who has seen behind the curtain of Pottermore says  "it is breathtaking in scope, detail and sheer beauty". And that's at the heart of this social media success: it's a genuine mystery. Just as the charm of the Potter book releases came from the details of the plot being kept strictly secret, so this latest venture, whatever it is, has the virtue of being an unknown quantity.
The announcement will be huge -- that much is guaranteed by who it is coming from and what it is about -- but it has already gathered significant momentum, without needing a big push from the mainstream. I find this all rather refreshing when compared to the business of how information is usually handed out -- most of the time, when a press conference takes place, everyone attending has already read the press release, filed a piece in advance and is entirely aware of what's going to happen; often, the details are leaked so it can turn up in newspapers' first editions.
This time, though, we really don't know. And that's keeping the magic alive.