If you've decided to move information around on your site, it's a good idea to let search engines and users know about the change. There is nothing more frustrating than going to your favorite site and clicking on a broken link because a directory structure just changed and the programmer made some errors in converting the links (give him a break, he's human too). The best way to handle changes to a site is through redirections, and today we are going to learn about the good, the bad and the ugly of redirections.
In order to talk about the types of redirections we first need to talk about format. Depending on what platform your site is hosted on (Microsoft IIS, Linux, or Apache), you're going to have to edit some server files. For the sake of explaining this more easily, let's look at the Apache implementation. There's a file on Apache servers called the .htaccess file. This is essentially a text file on the server with directives to control server behavior as well as a spider's behavior when crawling through that site. To implement a redirection, the format is as follows:
RedirectPermanent /directory/old.html http://www.domain.com/new.html
redirect 301 /directory/old.html http://www.domain.com/directory/new.html
This is known as the 301 permanent redirect. This method is a powerful SEO tool when moving pages or even entire sites. By returning a status code of 301 when a page is reached, the spiders are being told two different things: content on this page has moved permanently, and to replace the old page in the index with the page being redirected to. This is essential in avoiding duplicate content with what's known as a 302 or temporary redirect.
The 302 is every SEO's nightmare. As opposed to dropping the old page out of the index, a 302 tells the spiders that content has moved temporarily. The spiders will actually keep the old page in the index expecting the content to move back to this location. The problem with this is that with two versions of the same page in the search engine index, some pretty nasty duplicate content issues could arise. Another tactic that some sites still use is the Meta refresh. We want to make it clear that under no circumstances should a Meta refresh be implemented! Not only are Meta refreshes counted as temporary redirects, spam sites have used this tag to deceive users and spiders. Thus, the Meta refresh is now flagged as a spam technique that could result in your site being filtered into supplemental results.
As a general rule of thumb, avoid any kind of temporary redirection, be it through an actual 302 redirect or a Meta refresh. Both can cause some nasty problems for your site.