By all indications, scapulimancy was a widespread practice throughout the early Chinese dynasties, particularly the Shang and Zhou dynasties. During these periods, apyro-scapulimancy and pyro-scapulimancy were widely practiced as a means of entrenching the power of the ruling classes.
However, prior to the Shang and Zhou dynasties, scapulimancy was prevalent in the Neolithic culture of Longshan, typically concentrated in the central and lower Huang Ho regions.
During the Longshan cultural period, this particular practice of divination was associated with an entrenched level of social hierarchy in both life and death. Essentially, institutional violence was prevalent in Longshan society. Certainly, the culture was a violent one: archaeologists have unearthed countless weapons in Neolithic-era Longshan graves. However, what is troubling is that the skeletons of ritually killed infants and adults have also been found buried in the foundations of buildings.
The ruling elite of the Longshan Neolithic era (the select few) held considerable power over the common peoples through the use of scapulimancy. These elite held the power of life and death in their hands. It isn't surprising that they protected this special knowledge of divination scrupulously and reinforced their power by military means. In death (as well as in life), there was a hierarchy. The rich had larger graves, and males had more elaborate burials. The inscriptions on the scapulae also showed intricate graphs, possibly the precursor of a writing system in China.
However, only the elite who wielded the practice of scapulimancy could interpret the meaning of the graphs. Ancestor worship was also predicated on the practice of scapulimancy. So, scapulimancy was prevalent during the Neolithic Longshan era and was a means by which the ruling elite reinforced their power and influence over the common populace.
1) China: A History (Volume 1): From Neolithic Cultures through the Great Qing Empire by Harold M. Tanner
2) Divination and Power: A Multiregional View of the Development of Oracle Bone Divination in Early China by Rowan K. Flad, Current Anthropology, Vol. 49, No. 3 (June 2008), pp. 403-437 (35 pages)