Since everyone is still slightly reeling and recovering from the upgraded Penguin addition to the algorithm, it was at a recent conference where Matt Cutts spoke about the Panda portion, and elaborated a little on why we are no longer being directly advised that it has been running.
In case you happened to forget, the Panda portion of the algorithm is there to help determine just how high quality your website content is. It checks on things like originality, relevance, and whether or not it’s over optimized as well. The spokesmen for search engines have always maintained that the content that you create on your website should be for the users, not the robots, and Panda was their automatic process in that regard. When you cruise around the news and blogs of the SEO world over the last few years, you can always find the posts every few weeks where someone verified through Google that an update either was happening, or had recently happened. And just a short couple of months ago, Cutts came forward and said they were no longer advising whether or not Panda was being refreshed, or run across the web and their index. The reason is actually quite simple, at present, Panda will be running every month over the course of 10 days or so.
The web is nearly an immeasurable amalgamation of pages, gifs, movies, sounds, information, basically if you can imagine it, it’s on the web somewhere. And while some website owners were hit in a big way by Panda and Penguin, the increase in frequency of it running is a very good thing. In the past, every month or so Google would have a big shakedown of the index, hitting the pages hard with an updated version of the algorithm to try and clean out some of the spammy sites and those that weren’t abiding by the rules. Ever since they came up with the additions of Panda and Penguin, there have been some fairly small changes to the size of the index, impacting only a few percent of the total sites out there, but when you’re talking about trillions of pages, even a small amount can become huge. Panda running for 10 days of the month every month is a good thing, just think of it that way. It helps keep the index fresher and more spam free than it ever has before.