A good article on it:
From the article:
For the foreseeable future dispersal will not be focused on transactional database environments, where RAID will continue to perform well and be combined with flash, for example. In these instances, multiple copies are warranted as data sets are smaller and of higher value. Dispersal will fit well with large scale applications such as social networks, medical images, certain government applications, archiving, intelligence applications and the like where storage will reach into the tens of petabytes in capacity.