A measure of how well the system interacts with end-users. Typical definitions refer to SoftwareUsability as a composition of several factors, such as:

	* Learnability
	* Efficiency/Throughput
	* User Appeal / Subjective Satisfaction
	* Memorability	(note this can differ from learnability - e.g. it's hard to learn to ride a bike, but easy to remember how to do it)
	* Usefulness.

The discipline concerned with studying and improving usability is HumanComputerInteraction. 

-- MichaelMahemoff

Software which is usable is OnMySide, and doesn't get InMyWay.