Bacon Bits
Legend
I think that most people play that magical darkness obscures its area. Otherwise its hard to visualize why it would be dark.
I tend to play it like a charcoal-black fog or smoke, though it isn't physical so wind cannot drive it off and it doesn't affect breathing. A spell of high enough level "burns" it off like the sun on a foggy day, or appears to repel the smoke.
As far as whether or not light from a magic item would penetrate it, I'm not sure how we'd rule it. It does make drift globes interesting, however.
The wording of that last paragraph of darkness is interesting, however. "Light" and "Darkness" are no longer spell descriptors, so does darkness really dispel any spell that produces light? Create bonfire? Color spray? Fire bolt? Burning hands? Produce flame? Sacred flame? Silent image? Faerie fire? Does a wall of fire effectively suppress the effects of a darkness spell, or does the darkness spell block the light of the wall? What about the radiant heat from the wall? Isn't that also light? Does the spell have to say, "creates an area of light"? I know how I'd rule, but it's certainly ambiguous wording.