Sony is involved with Pottermore on some level. But I agree with
jswinden: people are totally grasping at straws when they make statements to the effect that Pottermore is somehow going to positively affect,
save even, Sony Reader business. For all I know this development may have nothing to do with Digital Reading Division of Sony. Well, a Sony Reader with a HP skin perhaps... Yeah, like that is going to turn the tide.
If the Overdrive is providing the distribution facility, the books are going to be available on any ereader. What's there to encourage people to buy a Sony Reader? A nice decal? I remember when Sony used to offer special edition PRS-505's - did they sell well? I also remember Dooney & Bourke covers at $150 a piece. Yes, they were nice.
Which parts of Sony are involved with Pottermore project? Entertainment? Multimedia? Are the new Sony Android tablets being geared up for HP multimedia experience? Are we going to get a PRS-650 Deathly Hallows Special Edition with dragon skin cover included? I can only see speculation here.