Web design has been in the news a lot lately. Target has been sued because its website is inaccessible to blind people, and now there's news that grants.gov, the government website designed to streamline federal grant applications, doesn't work with Macs. Nor does the FEMA site where Katrina victims can apply for aid.
There's really no excuse for any of these problems. Not in this day and age, given the ubiquity of free, standards-compliant web browsers.
In the "old days" of web design, designers always had to make trade-offs between desired functionality and incompatibility with various browsers. Both Microsoft and Netscape had taken the original HTML specification and "embraced and extended" it far beyond what the standards authority, the W3C, could sanction. But eventually the W3C caught up, and the browser wars mostly settled down. Yes, Microsoft still likes doing certain things its way, but now that there are viable alternatives to its Internet Explorer browser (like Mozilla's Firefox, along with Opera and Safari for the Mac) becoming used by more and more of the public, programming in Microsoft's Internet Explorer-only code is becoming increasingly ill-advised and unnecessary.
In addition, starting a few years ago there has been an initiative to make websites accessible for people with disabilities. In fact, in 1998 Congress required all Federal agencies to make their sites accessible to people with disabilities. Now, even though Section 508 of the Rehabilitation Act doesn't apply to private entities like Target, there's no good reason not to make the websites compliant with the law. The effort it takes to build a website that works in all browsers is for the most part the effort it takes to make them 508 compliant. (Which means it's strange that the grants.gov and FEMA sites won't work on certain platforms. It would make me wonder if these sites themselves are in compliance with the law.)
The bottom line - the bottom line for any web development endeavor - is that it does not make sense to build sites any other way and shut out a large portion of the audience. Now, occasionally it can make sense to decide in favor of some certain functionality that can only work for a limited audience. But those occasions are usually limited to situations where the desired audience is itself a limited one. That can't be said for government sites - every citizen needs to be able to interact with them - and it doesn't seem like it should be said about a major retailer like Target. It wants to be able to sell to the largest market possible. So why on earth would it limit itself to selling only able-bodied people? Especially since it's fairly trivial to make the site work for everyone. In fact, if the site is going to work effectively for anyone it should be constructed in a way that happens to work for everyone. The fact that it boxes out handicapped people suggests that it shuts out many able-bodied ones as well.
When HTML was originally developed it was intended to be a simple mark-up language that would simply permit information to be conveyed over the Internet. The browser could decide however it wanted how to display it - the content wouldn't care. But it turns out that publishers of content did care. They wanted more control over how a page displayed, and so they found ways to manipulate HTML code to force pages to display the way they wanted. This only worked to a point, however, as different browsers still did things their own ways. The point of standards, therefore, was to try to give some consistency, so that a web developer could predict that a page would display the way it was intended on any browser. Ultimately the standards developed so that this result could be best achieved if content was separated from display. Only the basic, textual information would be coded, and then stylesheets would be used to affect how the page would look.
The benefit of splitting page development in this way is that it allows browsers to render consistent content in whatever way is appropriate for it. This means that both Internet Explorer and Firefox on computers can render it, mobile phones can render it, and specialized browsers for the disabled can handle it because they can all have their own stylesheets appropriate for them. If the site is standards compliant, it's well on its way to being 508 compliant as well.
In any case, it is not obvious what Target hoped to gain by using a web technology that wasn't so compliant. The goal of its site is to sell things. To do that it needs to list its goods in a promotional context and provide a mechanism for their purchase. Yes, the page also needs to look nice to make the store look appealing, but there's no aesthetic requirement so severe that could possibly require using an esoteric technology that provides an aesthetic at the expense of its information. It just needs to look nice; it doesn't need to win an art award.
Therefore, at minimum Target's choice is a bad business decision. The question is whether it might also be illegal. It's not subject to the Section 508 requirements, but it is generally subject - at least in the physical world - to the ADA. I'm not an expert on that law, but I would guess it does not speak directly to website requirements. The question then would be whether such a requirement could be construed to apply to its website. Offhand I think there's a plausible argument for it: the policy values behind requiring a store to be wheelchair accessible, so that the disabled aren't shut out from society, are just as applicable in the web context. An accessible website itself can help create the same inclusive effect as physical in-store accommodations -- perhaps even more so because it affords another, potentially more convenient avenue for the disabled to participate in the retail world. Plus it's likely easier to make an accessible site than make an accessible store. In fact, you almost have to go out of your way to build an inaccessible website, in defiance of any sort of best practices. A well-designed website is one that enables its intended audience to interact with it in the intended way. If that result doesn't ensue, the web developer has done something wrong no matter what the law has to say.