It does not matter whats on your website, if it's "Broken".

Commonly problems are experienced when websites have insufficient cross-browser compatibility, or the ability for a website to be viewed and work properly in multiple web browsers such as Internet Explorer, Firefox, Safari and Netscape.

It's a problem that we see often with sites that were “designed and left on the Internet” and they begin to age, but is not uncommon to appear in new sites that have not been adequately tested as well.
Other common irregularities visitors can experience include:

Pages skewing to the side or expanding well beyond a typical reader's scrolling comfort,
Colours changing,
Backgrounds disappearing, background images not wide enough, background images incorrectly repeating itself.
Fonts changing.
Tables expand in different operating systems.

The same website can vary in how it looks

: Internet Explorer

: Fire Fox

: Opera

8 major reasons web sites "break"

The major reasons that website appear broken are:

Programming Errors - Some browsers are more forgiving than others, so sometimes programming errors are only visible on some browsers.
Browser Quirks - Different browsers have different peculiarities that need to be countered in programming.
Font Sizes - User preferences can increase the size of your typeface by 50% distorting the appearance of your site.
Computer Types - Even when using identical browsers, your site may display differently on a MAC than on a PC. Many designers are not aware that Microsoft outsources the development of IE for the MAC.
Browsers - A web browser interprets one language (HTML) into another (your display). But as with any translation, there are different means of expression. Although there is a general set of web standards, there remains a lot of room for interpretation.
Screen Resolutions - While the standard for a MAC is 1024 X 768, most Internet surfers are limited to 800 X 600 or less. Many designers, when planning for screen width, fail to allow enough room for variances.
Browsers Versions - Newer browsers support newer versions of HTML. For instance, Netscape 6.0 is a complete rewrite. If you use Dynamic HTML pages that display well in 6.0, they may not display at all in 4.0.
Technology Changes - Web design, as opposed to print, has the added complexity of a constantly shifting landscape.

So what does this mean for your website?

Unfortunately, most website owners are unaware of the problem. Having spent money on their website and having it look okay on their computer, they are unaware a significant segment of Internet users can suffer display problems due to insufficient testing and ongoing support.

It's probable that your business and service has a number of competitors. Imagine if just 20% of visitors to your site experience difficulties, this can significantly detract from your site's ability to achieve it's purpose, either through losses in enquiries or even the loss of sales from an e-commerce site.

Initial and ongoing testing of your site should be among your top priorities and there may not be an easier way to improve your website's performance and "bottom line".

At mcWebs any web-development we complete includes testing on a range of browsers (including PC and Apple Mac), monitor sizes, screen resolutions and connection speeds. In addition, best practice standards are complied with to ensure that your site is as future proof as possible and ongoing compatibility is monitored as part of all subscriptions. As new browser versions are launched to the market mcWebs tests all client sites to ensure nothing is "Broken".