Desktop GPU naming scheme is going from the 700 series straight to 900.
The 900 series, anchored by the flagship GTX 980 and enthusiast GTX 970, will be "paper launched" in the second week of September. A paper launch means launch information and hardware will be sent to tech reviewers and influencers around September 9th, but the NDA won't lift until later in the month. Even then, cards might not be available to consumers until later in the year, but that is only speculation.
So why skip the 800 series name? The series designation isn't being totally passed over -- for now its used on several mobile-only Nvidia GPU components. The latest Razer Blade uses a GTX 870M, for example. Additionally, as VC puts it, "...if NVIDIA didn't rename 800 series to 900 series, we would have desktop 800 and mobile 900M series in relatively short time."
We've reached out to Nvidia for comment on the name change, and will update accordingly if anything comes our way.
Regardless of the name, it sounds as though new GPU hardware is close to launch, so hopefully that part of the rumor is true, name shift or not.