Google's -30 ranking filter penalty

What do you think contributes to receiving that penalty. I ve seen somewhere that possibly sitewide linking. If a website receives this penalty, then what can be done to remove it?

 

Remove the sitewide ?

 

I'm not sure why you call it "Google's -30 ranking", but there is a penalty if you get many low quality links in a short period

 

neah, it's not so easy...once you trigger such filters.. you're screwed

 

no, you're not screwed. been there couple of times. once for using COOP, which I surely removed, and filled a reinclusion request. once for a forum full of spam (didn't have time to moderate) - removed the forum, and now the site is back

 

but were they full on blown penalties where you were removed from index or were they ranking drops?

 

first time, i was out of index, second time ranking dropped bigtime.

 

adolix, how long did it took to return back to index?
have you returned on same place, which you were before?