Like so many other Google algorithm changes, "PANDA" and "FARMER" caused quite a lot of intentional panic, chaos and scrambling for many search engine marketers who depend upon search engine rankings for leads and affiliate and referral business.
The intentions of Google in making these changes to their search engine ranking methodology are noble. Google wants to keep relevancy of organic search results the top priority. This focus on relevancy and perceived neutrality is the reason why users love Google as a search engine resource, and why Google blew past all of its major competitors years ago.
SERPs), the alarm bells ring in Mountain View and Google seeks to change the rules of the SEO game to push "spammers" down or out of search engine results. Google wants quality results, pure and simple, their customers are the end-users making the search, not us marketing types seeking SEO nirvana.
What impact are "PANDA" and "FARMER" updates having on my own webpages and websites?
My experience with Google SEO updates, including PANDA and FARMER, going back to 2003, is that the impact has been beneficial or neutral to my niche B-to-B webpages.
I try to always follow the SEO content school of keeping web content concise, precise, original, and relevant to my target audience and markets, with good website navigation, etc. My focus on relevancy and precision has been working extremely well for organic search.
There is usually a lot of excited SEO marketing chatter whenever Google rolls out a publicized search algorithm update... these Google tweaks go on all the time, and many changes are made under the radar. The only people who appear to really need to be concerned about these Google updates and changes seem to be those with websites which have marginal or poor content, are 'spammy', and engage in nefarious 'black hat' practices.
Regarding Google search results overall, there is always room for improvement... but then again, all the other search engines like BING and ASK have plenty of room for improvement. Search engine rankings are dynamic and always changing. This helps make the search engine optimization game never boring and always very interesting!