To me, web copy editing isn't just grammar and punctuation (although it amazes me how many sites still desperately need that).
It's about building an experience that speaks to clients.
What are readers looking for, and (here's the key) what words would they use to describe it?
What are they afraid of? What do they really want (that higher level thing they can get through a product or service)?
When I was in Journalism School, I took a course called Creative Nonfiction, where we did a lot of playing around with "tones." We'd write a piece, and then we'd have to rewrite it five different times, trying to mimic the tones of different (insanely talented) writers.
It was brutal. For the first time, I had to get out of my own head and into someone else's. I had to practice saying things differently than how I would have said them.
At the time, I hated it. I had to "ruin" my writing, five times, plus I had to pretend I was someone else, which made my Gen Y "just be you" instincts bristle.
I definitely had no idea how applicable that little exercise would be to my future writing life.
These days, I play around with tones all day long. More often than not, I'm not me--I'm an ultrasound repair company, talking to radiologists. I'm a kitchenwares seller, talking to foodies and home chefs. I'm a scientist, talking to my peers.
In order to borrow those voices, I have to understand the people who use them every day. I have to get into the nitty-gritty of personal motivations and word choice and life context.
To me, that's real copy editing.
Because these days, "just make us sound good" ain't gonna cut it.