They've revealed other spoilers though for this season that have been documented in this thread through conversation or interviews as I believe Devil Eyes has pointed out before. Totally avoiding mentioning spoilers these days is nearly impossible IMO, being a spoiler junkie myself I don't mind much, but understand those who like to be surprised would go ape shit about it.
Re: Robin...I could be wrong or just not remembering at the moment, but I don't think we know what Robin has been doing since he was last seen. In fact I was pleasantly surprised that Buffy confided to Robin in the first place and wasn't expecting to see him. It makes total sense now, but for whatever reason I didn't think about Robin. It was really nice to see him and get some more awesome back story for Niki.