How can i know whether some of my keywords penalised or not?

[bava_seo]

Hi,
Few of some keywords are on top 50 position in google, but after then suddenly they got disappeared from google - google has penalised the site for that keywords but what might be the reason why google has penalised the site and the main is how can i find out for what reason my site is penalised for few keywords?
actually i heard that google will notify the clear reasons before penalising the site so that they can rectify it, but in my case it doesn't happened.
I Need to find out reasons why gogole penalized my site for particularly selected keywords - your solutions, experiences, views , opinions are most welcome

[bava_seo]

what a silent?

[bava_seo]

can anyone put your experiences here

[ZydoSEO]

Dare I ask? Have you purchased links from other sites or link farms? If so you may have been penalized indirectly by Google devalueing the source(s) of your inbound links. While you continue to pay the other sites for their links to your site, they might not be passing you any link juice.

If Google has dropped you for some reason, I believe they will somehow attempt to email the webmaster for your site to notify them that negative action has been taken against the site.

Have you checked your site's code for black hat SEO methods like hidden text and such?

Just a thought.