在以前一篇文章中谈过二级域名作弊的问题，其中也谈到了google在改进对二级域名的处理算法的时候会怎样去对待新开的二级域名——是否会遭遇信任度审核等。本月初seroundtable上发表文章称google开始把二级域名等同于网站目录，据称说法来自于MattCutts在Las Vegas PubCon上的发言。

News flash from Las Vegas PubCon. Matt Cutts informed us that Google will very soon begin treating subdomains and subdirectories the same in this fashion: there will be only 2 total urls from a domain in any set of search results, so no more getting 3, 4 or however many spots via subdomains. We didn’t get any more information than just that basic heads-up.

SEObook上发表一篇文章谈论google和二级域名处理相关的问题，说google已经改进了二级域名处理算法，“将二级域名看成是二级目录，而且限制了搜索结果页面上的任意网站结果最多显示两个”，以前提到的Subdomain Spam已经得到解决。也就是说在针对同一个搜索请求的时候，google将不会在同一页面显示众多的同一网站的二级域名站点。

在过去，很多大型站点能够利用二级域名站点作为有效的内容管理策略，并且在google搜索结果中占据优势地位，但是现在当google算法改变之后，又该怎样看待二级域名问题呢？依旧是老答案，如果二级域名站点内容真的有价值而且二级域名之间的内容不重复，那还是可以使用的，只不过在google搜索结果页面只会显示最多两个最符合搜索请求的二级域名结果而已。

也许当我们确认google在处理搜索其站点本身或者百度等这样的搜索请求时也采取这个二级域名管理机制的话，它的算法机制就是真的改变了。或者有些站点依旧会是例外？

Update：Matt Cutts在博客上发表文章回答了上述google和百度相似的问题。

This change doesn’t apply across the board; if a particular domain is really relevant, we may still return several results from that domain. For example, with a search query like [ibm] the user probably likes/wants to see several results from ibm.com. Note that this is a pretty subtle change, and it doesn’t affect a majority of our queries. In fact, this change has been live for a couple weeks or so now and no one noticed. The only reason I talked about the subject at PubCon at all was because someone asked for my advice on subdomains vs. subdirectories.

看来对于一些品牌类型的搜索请求，二级域名还是可以不限制展示次数的。