Is Panda rolling now?

Selected answers from the Dumb SEO Questions Facebook & G+ community.

• 
  ?ukasz Rogala: Is Panda rolling now?
  I see huuuge increase for domains having issues which feed Panda algorithm.
  They loosed visibility exactly month ago and now they are back (we were cleaning index because of duplicate content issues - about 16 thousands subpages removed due to cleaning.
  
  Fun fact - Google totally gives a sh*t about redirecting old URL structure to another so I had to make 404 on every single duplicated/wrong/broken URL and remove 16k URLs manually.
  
  You can laugh loud at me on Dumb SEO Questions hangout. :D
• 
  Jim Munro: Nobody is laughed at, ;Łukasz, let alone friends. :)
• 
  Tim Capper: On mobile at the minute, will take a look tomorrow.
  
  Are you saying you redirected, canonicalised the pages before and no recovery, so you have now 404d them ?
• 
  Dan Petrovic: +Łukasz Rogala ;I'm updating the article as I find new stuff. Care to share any more data or examples? ;http://dejanseo.com.au/big-day-serps-yesterday-bigger-panda-4-1/
• 
  ?ukasz Rogala: +Tim Capper there was problem with broken htaccess which allowed uscto create and index almost every URL with random text. So we had urls like domain.com/product?=qwfvhyy and so on.
  First I've scraped whole search results for this domain (combined GWT search queries data and site:domain.com) to be sure what is indexed and check if should it be indexed or not.
  So basicly domain has about 1000 subpages. After scrape there was about 17k of URLs.
  After deep analysis I recomended redirecting every broken URL to correct version via 301 redirect. We were not able to use correct canonicals on broken pages due to script problems.
  
  After changes - after 2 weeks - Google did not temove broken URLs from index. It was Ignoring the whole redirections.
  
  According to previous Google Webmasters Office Hours hangout with +John Mueller I thought that Google is indexing it because there is traffic on this URLs and they can be what users are looking for.
  No traffic. No purpose for indexing. But broken URLs feeding Panda still in Index.
  
  So to be sure about removing those pages - we made 404 on broken URLs and were manually removing via Google Webmaster Tools.
  
  It looks like it is full recovery. Domain loose its visibility month ago. And now is back (also with 3x better CTR than before).
• 
  ?ukasz Rogala: +Dan Petrovic I'm on mobile now. When I will get to my notebook I will send you my thoughts.
• 
  Sam Billings: Hi Lukasz, can you tell me more about what you did to recover in Google? What kind of pages did you delete? Did you make url removals in webmaster tools? How well did you recover?
• 
  ?ukasz Rogala: +Sam Billings ;each case is different when it comes to Panda. In this one - I discovered huge issue with duplicated URLs. I can drop you more info on Hangouts.
  
  About "how well did I recover: I'm checking everything now and it's clearly full recovery.
• 
  ?ukasz Rogala: Ranking changes here:
  http://imgur.com/AASsVEU