Google’s Minus 30 penalty

What is -30 penelty Filter ?
There is a talk about a new filter from google which is popularly known as " -30 filter " basically it is an penalty filter which is responsible for lowering down of pagerank and even de-indexing of pages.

What happens when a site is filtered out for -30 penalty ?
The interesting thing is that the penalty is not a ban, but a bump down of 30 spots in serp So it's nearly impossible to tell if you dropped because of a penalty, or due to some other reason.
Lot of people that ranked #1 now rank #31 and not only for their target keyword phrase, but also for their branded domainname.

Why Does Google apply this -30 Filter ?
When a site is found to be using some spamming techniques for improving ranking then Google may apply this filter for preventing spam.
If a site is connected in any of the following case then it is likely to be get penalized
*) If you try to get inbound links by spamming guestbooks and blogs then Google might apply the filter to your web site.

*) Using JavaScript redirects : JavaScript redirections might be misinterpreted as a spamming attempt and hence your site may get -30 penalty.

What after Google penalized you by -30 filter ?
The -30 filter seems to be an automated filter. If you remove the spam factors from your site then you'll probably get your rankings back after some time. You can also send a reinclusion request to Google.