The job description goes way beyond spell-checking and perfecting punctuation. An errant ellipse or extra space can be forgiven when what you're reading makes sense.
That's what copyeditors are supposed to do: make the reading make sense. That's why copyeditors are still relevant today, and why they probably will be for years (or decades) to come.
And here's a newsflash: copyeditors don't necessarily need to know the subject to do a great job. Case in point: once I caught a math error (me!) in a user manual I was editing on Chromospectography. And the wonderful copyeditor who has vastly improved the second edition of my hiking guide, 60 Hikes Within 60 Miles of Cleveland, managed that not-so-small task while sitting in her office in Birmingham AL. (Thanks, Amber!)
The self-published book business is booming, without copyeditors. But can you name a self-published best-selling novel? I'm pretty sure that's not a coincidence.
No matter what your business, you could probably improve it by hiring a copyeditor - or proofreader. Sure, there are differences between the two, but they're both important to readers (and writers) and quite relevant in 2011. Perhaps even more than ever, as our reading environment changes. (Ever heard of Google Reader, Kindle, or an iPhone app?)
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