Keyword Stuffing

Keyword stuffing is considered unethical. This involves packing keywords into a web page's content and meta tags to obtain maximum search engine ranking for those particular keywords or phrases. By overstuffing a webpage with keywords you could end up being penalised by Google.

Keyword stuffing and SEO
Content should always be topical and relevant and not duplicitous and underhand. Some unscrupulous SEO writers add words that are commonly searched online, such as ‘sex' to attract traffic. The battle for the top ten Google ranking is an intense one, and there is SEO techniques that can work and still be considered ethical. If you use underhand methods, you could be removed from Google altogether. Google has to stay on top of underhand keyword use because it would lose its effectiveness if irrelevant sites popped up at the top of its rankings. Google therefore are quick to act on any methods that are underhand.
Getting the balance with keyword stuffing

So how do you get the right balance? Using keywords extensively in copy is okay as long as the keyword density isn't too high. It's considered around 3 to 7% is passable, but reach 10% density and you will look like you're keyword stuffing. One clue to keyword stuffing is if the copy does not read clearly and smoothly or make complete sense. Forcibly inserting keywords at a high density will skewer the readability. Google impose penalties on pages they find that are over stuffed or over-optimized.

Watch your Keyword Density
Using keyword density skilfully then is important – using keywords in the title, opening paragraphs and headings helps, although again you should try not to overstuff. Using synonyms or related words can help. The key is to write for web users first and foremost and not just for Google spiders. The basic SEO rule is that ‘content is king'. Achieving keyword optimization to top the search results and being penalized for over stuffing is a fine balance. Using keywords in links or anchor text, domain names and files will help Google ranking if used correctly.
Keyword Stuffing - Counterproductive

Excessive keywords can simply end up alienating the user and being counterproductive. Keyword stuffing can also impact badly on your site's ranking, so it's important to focus on creating useful, content-rich information led copy that uses keywords in appropriate quantities and in the right context.
Remember, if you violate Google's webmaster guidelines you risk your Google ranking. For the best optimization, create original, useful and relevant copy.

For More and Useful information you can take a look out here, Great source for Google Stuff