Ten years ago, Microsoft’s Internet Explorer dominated the web with an 85% market share. The minor competitors like Netscape, AOL, and Opera could barely scratch its control. But soon, Mozilla Firefox rose to prominence, stealing almost 50% of the market share by 2008. Then came Google Chrome, the now-reigning-king, with an estimated 52% market share; Firefox trails with almost 30%. These days, Internet Explorer is far from the top-dog. The conservative figures peg it at around 20% market share — a far cry from the 85% of ten years ago.

Why has Internet Explorer fallen into such disuse? In simple terms, Microsoft got complacent, and let their competition get ahead of them. When Firefox entered the scene with tabbed browsing and an integrated search engine, it took two years before Microsoft included such features in Internet Explorer 6. By then Firefox had already achieved 30% usage. And by the time Google Chrome came out, Internet Explorer was so far behind in terms of speed, stability, security, and compatibility that it could no longer compete.

So I shouldn’t care about Internet Explorer?

Not so fast. Internet Explorer may have lost most of its hey-day users, but its far from irrelevant. A 15-20% market share is still 15-20% of potential customers for a business, and you need to consider the merits and costs of targeting your development toward those consumers.

Internet Explorer 10 (or IE10) takes almost no effort over basic web development. IE9 takes a little more, but not for most scenarios. In general, IE9 and IE10 have the same functionality as Google Chrome or Mozilla Firefox, and don’t take much extra effort to ensure compatibility.

But sadly, IE9 and IE10 are barely used at all. The lion’s share of Internet Explorer use still comes from Internet Explorer 8 (released in 2009), at 10%. For conservative estimates, that means that IE9 and IE10 usage is only 5%. IE9 and IE10 aren’t supported on the once-standard Windows XP. For many users who are uncertain about third-party browsers like Chrome or Firefox, that makes IE8 the only choice. Earlier versions barely see any use – anyone still using IE6 or IE7 can easily upgrade to IE8 unless they’re on an ancient OS like Windows 98.

So I should care about Internet Explorer!

Hold on a moment. IE8 is still relevant, but that doesn’t mean that it’s worth ensuring compatibility for. For some websites with simple stylesheets and organization, making the page look good on IE8 takes little effort. But for other websites it can take hours – or days for an entire site – and that time is money. Like all other business ventures, adapting your stylesheets to accommodate Internet Explorer is a bit of a gamble, and it can pay off or it can cost you.

But to truly decide whether or not IE8 compatibility is important, you have to consider two things:

1. How much effort will it take to make my website IE8-compatible?
2. How many of my potential customers are likely to still use IE8?

The first question is one for your developers, and it can be hard to gauge until you try it out.  The most common way to format for IE8 and earlier involves conditional stylesheets, which can let you handle errors that crop up when dealing with columns, background-widths, shadows, transformations, and a host of CSS3 and HTML5 styles (all of which aren’t rendered properly or at all before IE9). This code shows how to implement a conditional stylesheet for IE8:

<!--[if IE 8]>
 <link rel="stylesheet" type="text/css" href="css/IE8.css"/>
<![endif]-->

But that’s the easy part. The actual time-consumption comes when you have to start manipulating the styles on that stylesheet. Trying to duplicate a modern website using only the attributes that IE8 can support can be very difficult. Even changing a broken page in IE8 to a workable, albeit less-pretty alternative can take time that may not be worth it.

The second question is a question of marketing. IE8 is used by up to 13% of users in Asia, but only 7% in Europe and Africa. IE8 is also more likely to be used by businesses, especially ones that use older web systems or programs that only function on past Internet Explorer versions or Windows XP. On the other hand, IE8 is increasingly less likely to be found among the tech-savvy and the youth, who much prefer Chrome or Firefox or, at the very least, tend to have upgraded from Windows XP and thus can use IE9 or IE10.

In the end, deciding on Internet Explorer coverage takes knowledge about business, the internet, and web development. While it’s something that you could probably do yourself with enough time and research, you may consider hiring someone already skilled at it to handle it for you.