I'm going to keep this one real short, not that because I am lazy to write anything but because this news would only be relevant in the next couple of days. Basically after the whole "Harry Potter" franchise ended for most fans, the author J. K. Rowling still had it in her to share something mysterious for her fans.
What this really is an online reading experience that derives from all the other Harry Potter stories in the past. Now the specifics of this website is still unclear to most people, but generally readers would be able to participate with the stories and even to some extent share and participate in the stories as well!
In some sense this would be like the pinnacle of experiences for all you "HarryPotter-ism" geeks out there to really get in touch with what happens next to Harry Potter and the gang after killing Voldermort and before growing up to become parents themselves.
Perhaps the basis of this website is very clear, the entire franchise was based on story telling that was done by a mother who winged her way through when asked to tell a story from her children and now it is only right to give the same participation to their own fans that has supported them for so long.
So long story short, go check out the website on the link above (or here) and see what is really going on in the world of Pottermore. Mind you as I am writing this, you got about 3 days left to register in order to get something mysterious from the website itself. Go figure....