By flooding your website with unnatural or excessive keywords you can actually harm your site’s online ranking with search engines. Such artificial attempts at boosting SEO usually backfire.

Equally damaging is receiving payments for placing links on your site. These ‘link schemes’ are artificial attempts by site owners to buy their way to the top of search engines by creating the appearance of popularity around the web.

Below are resources from Google that address both of these issues.

• Link schemes – “Any links intended to manipulate PageRank or a site’s ranking in Google search results may be considered part of a link scheme and a violation of Google’s Webmaster Guidelines. This includes any behavior that manipulates links to your site or outgoing links from your site. The following are examples of link schemes which can negatively impact a site’s ranking in search results…”
• Use rel=”nofollow” for specific links – “‘Nofollow’ provides a way for webmasters to tell search engines ‘Don’t follow links on this page’ or ‘Don’t follow this specific link.’ Originally, the nofollow attribute appeared in the page-level meta tag, and instructed search engines not to follow (i.e., crawl) any outgoing links on the page.”
• Report paid links – “We work hard to return the most relevant results for every search we conduct. To that end, we encourage site managers to make their content straightforward and easily understood by users and search engines alike. Unfortunately, not all websites have users’ best interests at heart. Some site owners attempt to “buy PageRank” in the form of paid links to their sites. Google uses a number of methods to detect paid links, including algorithmic techniques. We also welcome information from our users. If you know of a site that buys or sells links, please tell us by filling out the fields below. We’ll investigate your submissions, and we’ll use your data to improve our algorithmic detection of paid links.”