It is a well-known fact nowadays that without SEO a Web site stands many chances of not being indexed by search spiders, therefore risking not being ranked high enough (or even at all) in the SERPs. The result: poor conversion rate.

This situation is quite easy to avoid by performing some “cosmetic” operations on a site. One of these operations, considered by some rather difficult and a bit time-consuming, but quite effective in the long run by others, is URL rewriting.

Why It Is Nice to Have Clean URL’s

There could be two very strong reasons for you to rewrite your URLs. One of them is related to Search Engine Optimization. It seems that search engines are much more at ease with URLs that don’t contain long query strings.

A URL like http://www.example.com/4/basic.html can be indexed much easier, whereas its dynamic form, http://www.example.com/cgi-bin/gen.pl?id=4&view=basic, can actually confuse the search engines and cause them to miss possibly important information contained in the URL, and thus preventing you from getting the expected ranking.

With clean URLs, the search engines can distinguish folder names and can establish real links to keywords. Query string parameters seem to be an impediment in a search engine’s attempt to perform the indexing. Many of the SEO professionals agree that dynamic (a.k.a. dirty) URLs are not very appealing to web spiders, while static URLs have greater visibility in their “eyes”.

The other strong reason for URL rewriting would be the increase in usability for web users, and in maintainability for webmasters. Clean URLs are much easier to remember. A regular web surfer will find hard to remember a URL full of parameters, not to mention that they would be discouraged by the idea of typing, one character at a time, the entire URL. And they could also mistype it, and not get to where they wanted.

This is less prone to happen with clean URLs. They can help you create a more intuitive Web site altogether, making it easier for your visitors to anticipate where they could find the information they need.

Webmasters will find themselves that maintaining static URLs is a much easier task than with dynamic ones. Static URLs are more abstract, and thus more difficult to hack. The dynamic URLs are more transparent, allowing possible hackers to see the technology used to build them and thus facilitating attacks.

Also, given the length of dynamic URLs, it is possible for webmasters to make mistakes too during maintenance sessions, usually resulting in broken links. Not to mention that, when static URLs are used, should it be necessary to migrate a site from one programming language to another (e.g. from Perl to Java), the links to the site’s pages will still remain valid.

Dashes vs. Underscores

This is an issue where people have different opinions. The Web sites that still use underscores for their URLs are becoming scarcer and scarcer. Some say that people who
still use underscores are “old school” while dashes seem to hold the upper hand these days.

Among the reasons for using dashes rather than underscores, we can distinguish some usability-related ones, such as the elimination of the confusion created between a
space and an underscore when the URL is viewed as a link, or when printing such a URL.

Other than this, the chances that a combination of keywords contained in your Web site is included in the SERPs increase exponentially when using dashes.

To exemplify: a URL that contains “seo_techniques” will be shown by the search engine only if the user searches for seo_techniques (but this kind of search is rarely performed); whereas searches for “seo”, “techniques”, or “seo techniques” give your “seo-techniques” containing URL a better chance of being displayed on the SERPs. So, it is safe to say that this humble graphic sign can help you more than you can imagine, by greatly improving your visibility on the Web.

How to Rewrite an URL

The principle of URL rewriting is actually setting a “system” on the host server that will allow it (i.e. the server) to know how to interpret the new URL format. What actually happens when one decides to rewrite the URLs of a certain Web site is masking the dynamic URLs with static ones. This means that the URLs that previously contained query strings with elements such as “?”, “+”, “&”, “$”, “=”, or “%” will contain the more search engine friendly “/” (slash) element and present themselves in a simplified form.
To help you with cleaning your URLs, there are rewriting tools and engines, some free of charge, other fee based.

Online / Open Source Tools

•free online URL rewriting
•open Source URL Rewriter for .NET / IIS / ASP.NET
•open Source rewrite-module tuned for ASP.NET 2.0
•mod_rewrite
This is the most common non-fee-based rewriting engine. It is a module from the Apache HTTP Server that allows the easy manipulation of URLs. The use of this module requires enabling the RewriteEngine on your Apache server. Then, rewrite rules must be defined, and you can even set conditions for each rule, thus allowing you to rewrite requests as they come in.

In terms of SEO, mod_rewrite can be helpful if you have complex URLs that contain more than 2 parameters. In other words, if one of your dynamic URLs is accessed, the mechanism behind mod_rewrite will “translate” it into a shorter, friendlier, static-looking URL.

Fee-Based Tools

•ISAPI_Rewrite
The Internet Server Application Program Interface (ISAPI) is another URL manipulation engine that functions in a similar way to Apache’s mod_rewrite, with the difference that it is designed specifically for Microsoft’s IIS (Internet Information Server).
•IISRewrite
IISRewrite is a stripped down implementation of Apache’s mod_rewrite modules for IIS. It is a rule-based rewriting engine that allows a Webmaster to manipulate URLs on the fly in IIS.
URL Examples

Below are some examples of how URLs can look before and after rewriting:

Example 1:

•Dynamic URL:
http://www.companyname.com/products/items.php?id=x&model=y&variety=z (before rewriting)
•Static URL:
http://www.companyname.com/x/y/z.html (after rewriting)
Example 2:

•Dynamic URL:
http://www.example.com/cgi-bin/gen.pl?id=4&view=basic (before writing)
•Static URL:
http://www.example.com/4/basic.html (after writing)
Conclusions

URL rewriting can bring you on the right track in the race for SEO (combined with other techniques that you may use for this purpose). But be aware that rewritten (and, presumably, better looking and more effective in terms of search engine ranking) URLs cannot substitute a poorly designed Web site.

So don’t expect miracles. Nevertheless, when you decide that your site needs a makeover and start rewriting your URLs, make sure that:
•You keep them as short as possible (to increase usability),
•You use dashes rather than underscores (to give yourself a better chance of ranking as high as possible in the SERPs),
•You use lowercase letters rather than uppercase ones (to avoid case sensitive situations), and
•The technology you have used cannot be detected in any of your URLs (to prevent possible hacker attacks).

Inline Hack for IE
* (star) can be used as the inline hack for both ie6 and ie7.

For Example:
Syntax: .selector{*property:value;}
.logo{*margin-left:10px;}

IE6 browser inline Hack
_ (underscore) can be using only for ie6

For Example:
Syntax: .selector{_property:value;}
.logo{_margin-left:10px;}

Firefox inline style
content:”\”/*” can be used for firefox only where IE cannot recognize it.

Internal Style
Use * html for ie6 and *+html hack for ie7

For Example:
Synatax: * html .selector{property:value;} , * + html .selector{property:value;}

* html .logo{margin-left:10px;} for ie6
* + html .logo{margin-left:20px;} for ie7

IE7 and Firefox browser Hack
Use html>body hack for ie7 and firefox.

For Example:
Syntax: html>body .selector{property:value;}

html>body .logo{margin-left:10px} will take only in ie7 and firefox

Mordern browser Hack or Firefox Hack
Use html>/**/body {} hack which will support only in both firefox2 and firefox3.

For Example:
Syntax: html>/**/body .selector{property:value;}

html>/**/body .logo{margin-left:10px} will take only in firefox.

Browser hack for Opera versions 9 and below
Use html:first-child {} for opera browser. Also you use
Syntax: @media all and (min-width:0px) {head~body .selector {property:value;}}

For Example:
@media all and (min-width:0px) {head~body .logo {margin-left:10px;}} only for opera

Firefox3 browser hack
Use html>/**/body .selector, x:-moz-any-link, x:default {property:value;} for firfox3 only.

For Example:
Syntax: html>/**/body .pro_yl, x:-moz-any-link, x:default {background:red;}

Google Chrome browser hack
Use body:nth-of-type(1) .elementOrClassName{property:value;} only for google chrome.

For Example:
body:nth-of-type(1) .logo{margin:20px;}

Safari browser hack
Use Syntax: body:first-of-type .elementOrClassName{property:value;}

Fox Example:
body:first-of-type .logo{margin-top:10px;} only for safari.

Hope this information will be useful for you. Please use the browser hacks in a proper manner. For example, you might know double margin bug in ie6. In such case you can use display inline which will render correctly by all the browsers instead of you using ie6 hack seperately.