There is always the fear that changes made to a website may affect the search engine ranking of that site. More often than not these changes are reflected in a redirect. There are a number of reasons why a redirect might be needed - pages have to be moved around, CMS platforms need to be switched or duplicate content removed. Since webmasters can use a number of different redirects, it is vital that they choose the optimum one to avoid jeopardising the search engine optimisation techniques that have been used on site.

Temporary Redirects
A common mistake most SEO neophytes make is using a 302 redirect, also called a temporary redirect. The drawback to a temporary redirect is that the Page Rank acquired by the content on the page is not transferred to the redirected page. Thus, the webmaster has squandered a ranking built up with hard work and diligent usage of SEO practices by simply misunderstanding how Google's algorithm works. Luckily, it is easy to verify if your redirects are 302s or not with a server header checker. Once you know which pages redirect temporarily, change them to a 302 redirect, that is, a permanent one.

Permanent Redirects
Most standard maintenance that requires a redirect should invoke the 301 redirect, known as a Permanent redirect. This allows the Page Rank to be transferred, since all links that point to the original URL each contribute to the SEO value of the page. There are a number of situations when an SEO professional would be required to create a permanent 301 redirect. Top on the priority list is to avoid dilution of ranking by duplicate content spread over multiple pages. Many websites suffer from this as the chronically recreate content. A smarter approach is to use a 301 redirect and revamp existing content retaining its value before enhancing it.

Conditional Redirects
While permanent redirects are good SEO practice and temporary redirects are the bad, the really dangerous kind is the conditional redirect. Matt Cutts, head of Search Quality at Google, has specifically warned SEO companies to avoid using the conditional redirect, due to risk of a Google penalty or ban. A conditional redirect is a 301 redirect served selectively to a search engine spider. This technique may be used with the best intentions but since it has been exploited by BlackHat SEO, it will get your website in a whole host of trouble. There are few situations where working around a conditional redirect is difficult for web developers, but never impossible.

As a web developer for an SEO company, it is important to think decisively about how you use redirects on web pages that are being optimised. Choose 301s over 302 redirects and avoid conditional redirects at all costs.