从昨天开始，好多大站的流量都明显下降，降幅在50%左右。分析了很多，都没找到原因。一直不愿意去想，是不是Google算法调整了，因为如果真是调整的话，基本上没什么办法的。果然，去Webmaster blog去看了看，一片文章Another step to reward high-quality sites中提到了最近Google将出一个新的算法来对付spam。原文如下：

In the next few days, we’re launching an important algorithm change targeted at webspam. The change will decrease rankings for sites that we believe are violating Google’s existing quality guidelines. We’ve always targeted webspam in our rankings, and this algorithm represents another improvement in our efforts to reduce webspam and promote high quality content.

然后抓紧去看看最近国外的新闻，有没有说这事的。search engine roundtable上4.24的http://www.seroundtable.com/google-over-seo- update2-15057.html以及4.25的http://www.seroundtable.com/google-webspam- algorithm-15062.html都围绕Google的Over Optimization Algorithm说了很多。

Well, Google said it is rolling out now, but trust me, based on the volume of posts in the forums and complaints, it is indeed being rolled out and seen by webmasters.

虽然Google说Google过度优化算法(Over Optimization Algorithm)即将推出，但很多站长已经通过网站排名和流量的变化确定，Google过度优化算法已经推出了，影响范围正在越来越大。Google官方的申明是：

the initial Panda change affected about 12% of queries to a significant degree; this algorithm affects about 3.1% of queries in English to a degree that a regular user might notice.

大约影响力3.1%的网站，但我个人感觉应该比这个范围要大。

其实过度优化真是个难以把握的东西，不知道到底什么算是过度优化。Google方面也没有透露一些具体的信号，说是害怕有人针对算法又做一些spam。

We’ve always targeted webspam in our rankings, and this algorithm represents another improvement in our efforts to reduce webspam and promote high quality content. While we can’t divulge specific signals because we don’t want to give people a way to game our search results and worsen the experience for users, our advice for webmasters is to focus on creating high quality sites that create a good user experience and employ white hat SEO methods instead of engaging in aggressive webspam tactics.

做SEO真是件不容易的事，搜索引擎的一个变化就可能让你一年的工作白白浪费。需要淡定，淡定！