Modern computers are set up so that they can use the SSD/hard drive as extra, much slower RAM. Typically, when normal RAM is full, and you need more, a page of data in RAM will be swapped for a page of data on disk. On Unix, they end up in something called the swap file or swap partition, and on Windows, the equivalent is called the page file. In the screenshot, someone's mounted their Google Drive as a filesystem, and told their computer to use it as the swap partition, so instead of swapping to disk, it swaps to the cloud. This is obviously way slower, but they're effectively now using the cloud as RAM.