Things don't do with your Keywords!
Now you know what the keywords are and what to do with them. But here i list out somethings that you should not do for your web site in regarding to keywords, otherwise you have taken your own risk from being banned from the search engine company.
As some of the mysteries of search engine are unveiled, some people try to expliot the search engine logic to rank their page high by using some techniques, like Keyword stuffing.
So my suggestion would be use the keywords when you need is far ok for search engine to seek you anyway.What is Keyword Stuffing?
Keyword Stuffing is a technique for search engine optimization (SEO). The basic idea is to repeat some unnecessary keywords in your page in the meta tag and other place elsewhere in your page.
But repeating too much may signal the search engine that your page is exploiting with unnecessary keywords in the content. Another way to do so is to use CSS to display a bunch of keywords out of your visible area in the browser. The noscript of javascript is also a place to hide. There are actually lots of place to think of.
Because of this, some search engines may raise a red high if they detect this kind of violation, some search engines even do not use this technique for ranking anymore.