I work as a copy editor and proofreader for a large high tech company in San Francisco. As you can imagine, the quality of writing is all over the place — some of it quite good, some quite bad, but most in the middle range — from okay to not too bad to pretty good. The biggest problem is jargon. People in tech love jargon — it makes their job so much easier not to have to think hard about what something means and how to express that meaning. Other problems include inelegant sentence structure and lazy word choice.