Well you can target unlimited keywords on your website but it will be useless if your target unlimited keywords on same page. you can create bunch of keywords and target them on different pages of your website.
PPC - Pay per click
Its where companies or (Search Engines) such as Google, Yahoo and Bing make all their money. If you click on an advert or link on Google, the company that you clicked on has to pay every time you click to visit their website. This is usually the top 3 links on the page, and...