Without going any further, he explicitly mentioned in the chat that there are sequels to the Storybook Series and the Superstars Series (referred to by him as Sonic and Sega, which apparently is now the final name). On these issues, he gave no further details.
We also asked if the Xbox 360 and PS3 versions of Sonic Generations had bonus stages, at least for Classic Sonic, and that "there could be bonus classic Sonic levels".
However, the most interesting comment came when a user in the chat room mentioned that Tails should have his own game, when out of nowhere, completely out of context, the official wrote the following sentence:
"Something like a Sonic Adventure 3 ... DS?. I mean, it's a good idea"
Obviously this could have been nothing more than a personal opinion, however, the fact that it was spoken completely out of context calls attention to what was said.