Anything that can be stored digitally and has value.
This can be video, audio, photos, text, and other digital files. These can be in the form of documents, spreadsheets, and even other presentations.
Value can be derived in many different ways. Cryptocurrency is opening the door to tradeable markets, giving the digital assets instant value. There are other digital assets that can derive their value privately, such as a deal between two entities on a web URL.
Digital assets are also forms of intellectual property. This can exist based upon the data it represents or some other digital file that it is linked to.