Back in August a couple of researchers at Havard announced that they were able to store 5.5 petabytes of data on a single gram of DNA. Each DNA base is encoded as a binary value and then read as a binary value. To read the data you just sequence the DNA as you would sequence any DNA. The advantages of using DNA to store data is incredible especially when you think you do not need air controlled rooms to house the DNA because you can virtually store the DNA anywhere. Additionally, you can have so many backups of the DNA that you can essentially ensure that data is never lost unless there is a catastrophe that affects the entire human race.
There are obvious issues with the idea of having a completely abundant form of storage, namely it can allow oppressive regimes to record everything and further restrict privacy than they already do. Nonetheless, if storing data on DNA becomes the norm it would fundamentally change how we store data, but also society with the result of being able to record everything ever. If we can even store our own data in our own DNA, now that would be pretty sweet.
Check out a summary of the details of how they accomplished storing the data here.