How long does it take for typical members of the community to learn relevant task?  How long does it take to perform relevant benchmarks?

Describe the ways in which your design you users interface considers the 5 measures of usability:
How long does it take for typical members of the community to learn relevant task?
How long does it take to perform relevant benchmarks?
How many and what kinds of errors are made during benchmark tasks?
Frequency of use and ease of learning help make for better user retention
Allow for user feedback via interviews, free-form comments and satisfaction scales