A very good argument for writing like we speak
One of my favorite writing resources, Copyblogger, made a solid argument for using common, everyday language in our marketing materials.
Turns out, writing like people speak is actually a good strategy for search. Product features and benefits are obviously important. But our products solve business problems, and if we address those (clearly and plainly) in our online content, we will capture a larger share of search.
So when you're writing for the web, read what you wrote out loud. Does it sound like something you would say to a coworker or customer? If it doesn't, reword it so it sounds more conversational. That's optimized content.