Lost 75% of my traffic on Oct 25, help appreciated

[Sire]

So I've been running coolquotescollection.com since 1997 (!) as a hobby project. I lost about 75% of my organic search traffic on the 25th of October, literally overnight. I've been doing a lot of research but I still don't know why I was penalized. Image attached.

I naturally thought this was because of Penguin (Oct 17, my drop was Oct 25). However, after checking backlinks I only discovered 11 domains with about 100-400 links each, the major ones were forum signatures and blog sidebars, 6 domains were spam sites / directories. They almost exclusively used the same anchor text (domain name or similar), so this doesn't seem like a black hat attack. Some of the directories used keywords in their urls however (like "funny quotes").
1. Is this really enough for such a heavy penalty?
I added these domains to be disavowed today, I'm aware this might take weeks or months to change.

I've automated so that pictures gets uploaded to my Facebook page with a link to my page. This started in early 2014.
2. Can Facebook links be considered link spam?
They don't even show up in webmaster tools.
Example: https://www.facebook.com/CoolQuotesCollection/photos/a.510328825689624.1073741825.326096120779563/615403025182203/?type=1&theater

I analyzed keywords and the major ones dropped between 2 and 6 positions. Notable exception: I seem to still rank nr 1 for "cool movie quotes" even though page is not optimized for that keyword.

Moz warned about over 5000 pages with duplicate content. It was a single page that used a querystring url parameter I have excluded in webmaster tools. I have now entered a canonical link on these pages. Example:
http://coolquotescollection.com/Home/TShirts?url=http-url-example...
http://coolquotescollection.com/Home/TShirts?url=http-another-url.......
3. Could the Google algo penalize this even though I have excluded the "url" parameter?

I have a lot of internal links in the page navigation. Can this cause problems? See the absolute bottom of this page where I have 94 links for example: http://coolquotescollection.com/laughs
4. Could a lot of internal links (navigation to page numbers) be the problem?

Some more facts:

• Site is http://coolquotescollection.com/
• Domain is 14 years old.
• The web site launched in Sep 1997, a year before Google! (Not relevant but you might understand why this is important to me).
• I haven't done any SEO work for at least 12 months, probably closer to two years.
• The only SEO work I've done is to optimize the pages, no link building at all, no black hat stuff.
• I'm automatically building a sitemap that contains all pages, see here: http://coolquotescollection.com/robots.txt
• I've used webmaster tools for years, haven't gotten any warnings. I checked backlinks there, also here from moz and ahrefs.

I'm annoyed that a quality content site can be penalized so hard (75% drop) when there are no, or just smaller issues. I'm just lucky this is not my business site, if so I would have gone out of business.

Any help in this matter would be greatly appreciated!

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[Sire]

Traffic decreased about the same on all pages. I was however surprised that the thin pages was 40% of all landing pages. This might actually be one explanation. It still doesn't explain the extremely sudden drop however, since I've read content-related algo hits are usually more gradual (over one or several weeks). I might be wrong however.

Stats:

75% decrease in traffic on thin quote pages (40% of all landing pages)
80% decrease in traffic on all other content rich pages (60% of all landing pages)

My plan now is to hide (NOINDEX) the thin pages.(http://moz.com/community/q/noindexing-thin-content-pages-good-or-bad)

[DennisSeymour]

That's right. You might want to check your analytics. See if your traffic on those thin pages dropped. You might also want to check your indexed pages on webmaster tools to see if it dropped.

If you see signs in any of those, then you found your main problem.

That's the only thing I would work on right now actually. Edit them or redirect to meatier, relevant pages.

One thing I'm sure of is that this isn't Penguin as you never really did create any links to it

[Sire]

Yeah I've heard this as well. Some still seem to think Penguin only happened on the 17th of Oct, but I find that hard to believe.

I manually looked into all domains with more than 20 links to my site and disavowed all spam and low quality sites. Did you mean something else?

[Sire]

I assume you mean the detail pages with just a single quote on? Like http://coolquotescollection.com/1/
Do you think I would see improvements if I removed these pages completely? Or is there another solution I can try?

[MickEdwards]

I'd still look at the link profile as well.  Penguin 3.0 is still rolling out http://searchengineland.com/google-penguin-3-0-rollout-still-ongoing-209886.  Look into the profiles/content of the linking domains to rule you out being collateral damage as well.

[DennisSeymour]

There was an update during that final week of October but it wasnt widely reported on. I think it's even bigger than the panda/penguin that came before it. I still dont have a conclusion on what it was but looking at your site, I would think it could be about the content. The indexed pages are really thin, hence possibly being the cause for the big drop.