In the software world, a "portable application" is a program that does not require installation and can run from a removable storage device (like a USB flash drive) without leaving traces on the host computer’s registry or file system. Users love these for several reasons:

When you see a "1 Link" download for a portable version of Microsoft Project, it typically refers to a modified version of the software. These are often created by third parties using virtualization tools to bypass the standard installation process.