Originally Posted by jgf310

prepare to be informed by a bunch of knowledgable cyclists that you cannot compare your own average speed to the average speed of internet posters around the world.
actually if you do the same route a lot, and if you can track the moving average, then average speed will be useful.

obviously, it's easy to measure, which is precisely what makes it so useful - especially for beginners..

also..., have you ever noticed that in a race..., the guy with the highest average speed wins?

as far as why your average is not improving any more..., i have no idea, but i can tell you i got faster by joining some group rides that were faster than i was riding, and building up to their speed.