The process is very simple, article rewriter tool will scan through the given content for the words that it can replace with a synonym. If article spinner will come across a word that it can replace with a substitute then it is switched with one of the suitable substitutes and is highlighted, making it easier for you to identify. However, you can click the word if you want to revert to the original text, find a different suggestion or add your own text.
Think of it this way: What do you have more chance of hitting, a distant, tiny target or the broad side of a barn? For the sake of search engine optimization, you want your website to be the broad side of barn. The more quality articles, or unique readable content, your website or blog offers to search engines (and therefore the general public) the more exposure your website will receive from major search engines.
But it is the most important that the spun text, especially with version 2.0 usually passes CS test, and Google cannot even see it as spun content. Such as content can be used for links building as well as on money sites and qualitity is pretty good, as you saw in the example. It is much better than other article spinners with similar pricing as they do not get the right meaning of each and every word, so the rewrites sometimes looks funny/strange. It is of course much better than any free article spinner/rewriter I have tried.

Don't you hate it when your synonyms make no {sense|perception}? Don't settle for the "content garbage" that most spinners vomit out. WordAi can tell subtle differences between words and makes sure each synonym it picks makes complete sense. This gives you articles that are automatically readable, without you needing to spend countless hours fixing them up!