Sony has developed technology which allow for storage density of 148GB per sq in, totalling 185TB per tape, they plan on comerciallizing this technology. There has been strong growth in this market undoubtably due to big data given the emergence of 'cloud computijng', mass survaillance and huge data mining/recording companies (facebook for example).
Sandisk on the other hand has also been bussy, they recently announced a 4TB 2.5in SSD and plan to release 8TB and 16TB SSDs soon after, unfortunately It seems like durability (in terms of writes) sharply declines, which probably isnt that much of an issue in much of these cloud based and caching applications. They are a comercial grade product and use 19nm eMLC NAND flash.
Seagate has also been busy, they developed a 6TB enterprise drive rated for 550TB/Yr, max sustained speeds of around 216MBps and is composed of 5 platters of 1.25TB density each. Interestingly they managed to do this using only 5 platters, in a non-sealed unit, unlike WD-HGST which did this in seven and is a much more expensive process as they must be sealed with helium. Both are priced around 600USD or 0.10USD per GB, which is about 2.7x a standard Segate drives per GB cost.
It appears that big-data (such as social media, survaillance and 'cloud' computing) is a big buisiness and will continue to push the development of data storage, for good or bad, as companies follow the money.