It is not a tangible entity, but a place that gives users the ability to store, synchronize, stream and share content on a relative core, moving from one platform, screen and location to another.
The main drawback, however, is that the speed of the transfer rate is only as fast as the network connection the data is accessed over and can therefore be fairly slow.
This enables both wired and wireless computers to access the USB hard drive and use it for storage or for retrieving files a user needs to share on the network thereby acting like a cloud.
The challenge for the home-made cloud is that in order to set it up a user has to have a certain degree of skills in technology and network setup.
If this setup is not done by a tech expert the biggest issue will be security and leaving the files accessible to anyone with technical knowledge.