As it has already been a while since the first hybrid HDDs (more recently called solid-state hybrid HDDs / SSHD) were introduced, Seagate figured it was time it broadened the scope of these storage devices.
Seagate's hybrid hard drives have been available only to notebook makers for the past five years.
The company will continue to sell 7mm and 5mm drives (0.27 and 0.19) to makers of laptops, but will begin offering HDDs with integrated NAND Flash chips to server builders and desktops are well.
It did not give a specific time frame for it though. We suppose it is possible for some prototypes, or maybe even sales-ready models, to be released at the 2013 Consumer Electronics Show (CES 2013), or maybe even in time for Christmas. We cannot know for certain, however.
At any rate, whenever Seagate decides to make its move, Western Digital and Toshiba will be there to match it, assuming they don't move first.