You can find lots of use in a word mixer in todays seo / sem campaigns. They make softwares that can mix up the words of your article using a thasourus that basically replaces one word with another word that means relatively the same exact thing. Such software can be tricky to master though as lots of times they can render an article jibberish with bad gramar hard to read for the normal viewer.
Always remember when using a word mixer that you should be optimizing for the viewer first and not the search engines. Naturally you do want 100% unique content, but your readers are the most important aspect of your web page. A reader is ten times more likely to take you seriously or click an ad on your site if the content isn't total jibberish.
Another thing to consider when writing content with the assistance of topic mixers is that they will normally pass a copyscape check unless someone else mixed their words with the same settings. Then you'll risk duplicate content which doesnt do you any good at all since google will just drop your page into the supplimental index due to it being a duplicate.
Use your word mixer wisely and always double check the content afterwords for at least basic gramar errors and to be sure its not duplicated with anyone else that spun content.