There is significant overlap in the requirements for cloud and cloudlet. "mobile device - cloudlet - cloud". Cloudlets need practical applications to incentivize cloudlet deployment. By 2015 cloudlet based applications were commercially available. Meanwhile, there are a few but important differentiators between cloud and cloudlet. When used in this way, each cirrocumulus element is referred to as a "cloudlet". However, developers cannot heavily rely on cloudlet infrastructure until it is widely deployed. Each cloudlet appears no larger than a finger held at arm's length. The concept of cloudlet is also known as follow me cloud, and mobile micro-cloud.