It's true that when it comes to grammar there are a lot of hard and fast rules, but it's also true that there are hundreds, maybe thousands, of issues that are dictated by style.
How Are Style Guides Used?
A style guide is a very, very good thing for editors. It will keep them from wasting time reworking documents to fit their preferences.) A style guide is a very good thing for companies and publications. It keeps all their works consistent, which makes their overall offering feel more professional. People might not consciously notice it, but they'll feel like something is wrong if things aren't consistent from page to page. A style guide is also a pretty good thing for writers, because it saves them from spending time waffling about which way to do things (and from fighting about it on e-mail lists). It can also save writers from offending unreasonable editors who have strong preferences that they otherwise fail to communicate.
So, the bottom line is when you start a project with a new company or publication always try to get the style guide, and if you hire writers make sure you have a style guide to give them.
Thank you to everyone who has left reviews at iTunes, I really appreciate it; and if you're sitting at your computer right now and haven't already left a review, why don't you do it right now? It doesn't hurt nearly as much as seeing two spaces after a period.
Sample Style Guides
The Economist This is the closest thing I can find online to the kind of house style guide I'm talking about in this episode.
This is cool: A Language Map