We produce about one report per week, < 20 pages for venture capital groups about to invest into some company. That's a pretty tricky combination of elements, you are writing for a non-technical audience about technical findings.

The companies we work for tend to have people on the business side that have certain ideas about requirements which then need to be translated into technical specifications, typically so that some outsourcing company can make soup of it.

In both cases mistakes can be quite costly. There is this thread right now about 'what HN has given you', and if there is one thing HN has given me it is that it has made me a better writer (that, and blogging), which turned out to be a super useful skill.