Keyword stuffing and Hidden text manual are being used more and more nowadays but with its popularity it is even being warned again and again by Google not to be used so frequently. Both these terms are some time considered to be 50 lines long text with footer of a webpage but actually it is stuffing of keywords just for the sack of search engine and not for the readers or audience.
It was earlier used with apparent ease but now CSS is used to submerge the text or simply hiding it in the text. Keywords stuffing can easily be defined that there are so much keywords on the page that they make the text look non- under stable which turns the Search engine to discard such text and penalize it if done repetitively.
Matter which makes this strategy a loss is its damager to user experience. Whenever a user searches for a keyword with your text and lands on your page, he wants a text which is not over emphasized with the specific keyword but only to be placed with appropriate frequency and utility.
If you recive a warning for Keywords stuffing and hidden text from Google then waste no time and remove the described fault lines from your text as soon as possible. I can easily be found in the source code of your page either at the top or at the bottom. Cutts was very clear when he stated that most of such actions are related to a hacked site and major portion of that comes from WordPress sites. In case you receive complain regarding a website of your on WordPress then the first securing point for you is to check whether you are hacked or not? After confirming a hack you must upgrade WordPress and all of its plug-ins and then start on with your cleanup.
Documentation is essential for Google if you want a recovery or get off the watch-list of Google, Document every fault you found and the appropriate steps taken by you to remove them