I am going to go with the keep the ebook reader as simple as possible. Part of the beauty of an ebook reader is that it is designed and optimized to do one thing well, read books. Logical extensions like being able to procure books through the ebook reader make a lot of sense as well... but only so long as they don't compromise the reader's primary function.
Lets be honest, meaningful discussion of ebooks generally requires more than a status update on your facebook or twiiter feed. Discussion forums like this are a far better choice... of course they also much easier to use with a full keyboard than with the limited input options on even devices like the Kindle.