good one, but i would like to state here something other than ordinary. yes it has insightful features to be used to optimize your website for search engines. but in case - whether the content includes a specific focus on keyword or not - we don’t need to worry about it much now, because google which is the prime focus of search engine marketers, now considers content which is not just keyword focussed. What i mean say is
if your keyword is “how to use microwave”
you can not use this exact keyword throughout the web page, it will look absurd and not user friendly, you can use words in this particular phrases no of times, but not the exact phrase. And these plugins estimate the no. of times the exact keyword has been used. So about content, we have to be thorough, fresh,keeping the reader in mind than depending upon any plugin.