Google is the largest Search Engine on Internet and best way of bringing traffic to the websites. Google keeps on working to improve its Search quality to provide best results to the visitors. For this purpose Google has introduced various types of penalties which are for degrading ranking of those websites in search results who are not having good quality content or violating other Google quality guidelines like bad user experience, keyword stuffing etc.
There are several types of Google Penalties which i am going to mention below with details:
1 Manual Penalty
Its one of the most dangerous type of Google Penalty which can kill 90% of your Traffic coming from Google. In this type of penalty someone from Google Webspam team manually reviews your site and penalizes it for violating Google quality guidelines like scraping content or having unnatural links. if this penalty is imposed your site results may go down 5 pages or can be completely removed from Google search if violation is serious. usually after this type of penalty website owners gets a message in Google Webmaster tools in which reason of the penalty is told. if you get such a penalty on your site then you will need to make necessary changes and then send a reconsideration request to Google. they will review your site and if violation not exists anymore then manual penalty will be removed and you will be informed through another message in Google webmaster tools.
2 Google Panda Penalty
this penalty takes place when Google makes change to its algorithm to lower the ranking of bad quality sites and reward good quality sites. Google keeps on releasing Google Panda update time to time. if you get hit by this penalty then you need to remove poor quality content and start adding good quality content. you will also need to do patience to bounce back.
3 Google Penguin Penalty
This penalty hits those sites who gets too many unnatural links.
4 EMD Penalty
EMD Exact match domain penalty is for those sites who ranks well in Google just for having keywords in the domain while their actual content is not of great quality.
5 Above The Fold Penalty
Google introduced this penalty in mid of 2012 to target those sites who where having too many ads in above the fold area while the actual content was below.
6 -30 and -950 Penalties
These penalties are usually imposed on those sites who are involved in acts like keyword stuffing, hidden text, cloaking and doorway pages. these penalties remains for 60 to 90 days and after that expires.
So these are different kinds of Google Penalties. they key to safe yourself from these penalties is to create original good quality content and following all the Google quality guidelines.