Imo it is not possible for google to detect properly spun content, it is not worth computing power it requires. They can do this using ngrams for example, but it is uses a lot of queries. And for example article spinner I coded beats this algo, so google cant detect that the content is spun. Manual spinning is also good but it takes more than 30 minutes per article.
To rank your website in search engines you have to post content at your website on daily basis. If you have more than 2 websites then it is almost impossible to write unique content on all those websites. Because for proper blogging you have to keep an eye on word count of your blog post. To do this task webmasters use article spinning tools so that they can post articles to their domains daily. Paraphrasing Tool is also used by students when they have less time to submit their assignment; they just copy content from the internet, rewrite it, remove grammar mistakes and submit it. According to the webmasters, we have the best sentence rewriter tool available online.
There are a wide range of applications that might benefit from the content rewriting capabilities of ArticleRewriterTool. The obvious applications include building content for your website or blog. Other applications include any kind of essay or creative writing (virtual or not), twitter, newsfeeds, Craigslist posts or even paid article writing services.