If you own a site, you have probably already registered it to be listed by Google Search. Then, if you want to improve your number of visitors, you must use some Search Engine Optimization techniques.
So, let's suppose that your site is now listed first, second or maybe the third when you type "software" and press Search in Google Search Box. But then, suddenly, the website is ranked on the 31st position. Of course, you're angry, but what happened?
Well, you have probably violated Google's license agreement, so you're site is now penalized with 30 positions (points).

Now, the questions: why am I being penalized, when it happened and how can I remove the 30 points penalty?
Nobody can answer better that a Google employee, in the person of Adam Lasnik, "Search Evangelist for Google" as he entitles himself.

"Some good questions Webmasters in this situation or similar situations can ask themselves: Is my site providing unique and compelling content? Would most consumers find my site to be more useful than others in this space? Am I abiding by all of Google's Webmaster Guidelines?
If the answer to all of those questions is yes, then it's wise to doublecheck, then be patient / continue to develop your site. And optionally file a reinclusion request, if you've fixed issues associated with previous guideline violations," Adam said.

"If you've been penalized (in any form) due to a violation of the Webmaster Guidelines, cleaning up the infraction and filing a reinclusion request is the fastest and most surefire way of having that penalty removed," he added.

So, if you take a 30 points penalty, you can send Google a reinclusion request and pray to be forgiven by the company.