On Friday, Google officially wrote about their recent algorithm changes (commonly known as the Panda or Farmer update) for the first time, at least around what it hopes to achieve and how webmasters can better align their sites with the search engine's latest goals and philosophies.

The following is taken directly from a post by Google maven Amit Singhal, as posted to the Google Webmaster Central blog last Friday morning:

 In recent months we’ve been especially focused on helping people find high-quality sites in Google’s search results. The “Panda” algorithm change has improved rankings for a large number of high-quality websites, so most of you reading have nothing to be concerned about. However, for the sites that may have been affected by Panda we wanted to provide additional guidance on how Google searches for high-quality sites.

Our advice for publishers continues to be to focus on delivering the best possible user experience on your websites and not to focus too much on what they think are Google’s current ranking algorithms or signals. Some publishers have fixated on our prior Panda algorithm change, but Panda was just one of roughly 500 search improvements we expect to roll out to search this year. In fact, since we launched Panda, we've rolled out over a dozen additional tweaks to our ranking algorithms, and some sites have incorrectly assumed that changes in their rankings were related to Panda. Search is a complicated and evolving art and science, so rather than focusing on specific algorithmic tweaks, we encourage you to focus on delivering the best possible experience for users.

What counts as a high-quality site?
Our site quality algorithms are aimed at helping people find "high-quality" sites by reducing the rankings of low-quality content. The recent "Panda" change tackles the difficult task of algorithmically assessing website quality. Taking a step back, we wanted to explain some of the ideas and research that drive the development of our algorithms.

Below are some questions that one could use to assess the "quality" of a page or an article. These are the kinds of questions we ask ourselves as we write algorithms that attempt to assess site quality. Think of it as our take at encoding what we think our users want.

Of course, we aren't disclosing the actual ranking signals used in our algorithms because we don't want folks to game our search results; but if you want to step into Google's mindset, the questions below provide some guidance on how we've been looking at the issue:

• Would you trust the information presented in this article?
• Is this article written by an expert or enthusiast who knows the topic well, or is it more shallow in nature?
• Does the site have duplicate, overlapping, or redundant articles on the same or similar topics with slightly different keyword variations?
• Would you be comfortable giving your credit card information to this site?
• Does this article have spelling, stylistic, or factual errors?
• Are the topics driven by genuine interests of readers of the site, or does the site generate content by attempting to guess what might rank well in search engines?
• Does the article provide original content or information, original reporting, original research, or original analysis?
• Does the page provide substantial value when compared to other pages in search results?
• How much quality control is done on content?
• Does the article describe both sides of a story?
• Is the site a recognized authority on its topic?
• Is the content mass-produced by or outsourced to a large number of creators, or spread across a large network of sites, so that individual pages or sites don’t get as much attention or care? 
• Was the article edited well, or does it appear sloppy or hastily produced?
• For a health related query, would you trust information from this site?
• Would you recognize this site as an authoritative source when mentioned by name?
• Does this article provide a complete or comprehensive description of the topic?
• Does this article contain insightful analysis or interesting information that is beyond obvious?
• Is this the sort of page you’d want to bookmark, share with a friend, or recommend?
• Does this article have an excessive amount of ads that distract from or interfere with the main content?
• Would you expect to see this article in a printed magazine, encyclopedia or book?
• Are the articles short, unsubstantial, or otherwise lacking in helpful specifics?
• Are the pages produced with great care and attention to detail vs. less attention to detail?
• Would users complain when they see pages from this site?

Writing an algorithm to assess page or site quality is a much harder task, but we hope the questions above give some insight into how we try to write algorithms that distinguish higher-quality sites from lower-quality sites.

What you can do
We've been hearing from many of you that you want more guidance on what you can do to improve your rankings on Google, particularly if you think you've been impacted by the Panda update. We encourage you to keep questions like the ones above in mind as you focus on developing high-quality content rather than trying to optimize for any particular Google algorithm.

One other specific piece of guidance we've offered is that low-quality content on some parts of a website can impact the whole site’s rankings, and thus removing low quality pages, merging or improving the content of individual shallow pages into more useful pages, or moving low quality pages to a different domain could eventually help the rankings of your higher-quality content.

We're continuing to work on additional algorithmic iterations to help webmasters operating high-quality sites get more traffic from search. As you continue to improve your sites, rather than focusing on one particular algorithmic tweak, we encourage you to ask yourself the same sorts of questions we ask when looking at the big picture. This way your site will be more likely to rank well for the long-term.

In the meantime, if you have feedback, please tell us through our Webmaster Forum. We continue to monitor threads on the forum and pass site info on to the search quality team as we work on future iterations of our ranking algorithms.