Was my site hit with a delayed Panda penalty?

[tact]

Hi all,

We launched a major update of our site in the middle of June. We have lots of pages and were indexed very quickly, and started ranking well for long tail terms. Last week, over Tuesday and Wednesday (Sept 11-12) our organic traffic suddenly dropped over 60% as our pages started ranking much lower.

One issue we discovered was that our site was responding to all subdomains, not just www, and Google did seem to be crawling two alternate subdomains -- Webmaster Tools shows crawl activity, but no pages indexed on these. We fixed that problem a couple days ago (all subdomains 301 to the www).

I know that Google put out their "diversification" update last week. Is possible that this somehow triggered a Panda reevaluation of our site? Like maybe it took some time for G to figure out that our site fit the Panda profile. We have a lot of pages because we generate a separate page for each product variation.

Indexing continues -- we now have over 500k pages indexed and Google is crawling faster than ever, about 30,000 pages per day.

If not a Panda penalty, what else could cause such a sudden drop?

Thanks.

[edited by: tedster at 6:50 pm (utc) on Sep 19, 2012]
[edit reason] removed specific detail [/edit]

[tedster]

Hello tact, and welcome to the forums.

I'd say no - it's not Panda. Panda's Data Refresh was run on September 18, so any change that kicked in on September 12 was not the result of a Panda effect.

However, September has been a very active month for changes - see Google Update Bacon [webmasterworld.com] where we discuss the combination of these various separate and smaller steps as one major update we are calling "Bacon."

One change that was closer to September 12 was the Domain Diversity [webmasterworld.com] update - it was announced on September 14 and had clearly been run "earlier in the week", therefore BEFORE that day.