With a profound sense of importance, our infamous design engineer,
This technology allows your browser to download simple images and text and apply graphics filters from inside the browser, giving you the ability to display effects like drop shadows, weird glows, and a host of other visual effects at a low cost to bandwidth.
The concept behind the filters, which you can explore in more depth in Taylor's piece, is to offer a way of extending the presentational power of the Cascading Style Sheet specification without having to change the language itself; it's a way of piggybacking new functions without rewriting the spec every time. And while this might seem like an obvious direction to move in, it may well be a long and arduous journey. Let's take a look at the issues.
You can start by thinking of CSS filters as much like <object> in HTML. Imagine, for example, if the Web community had to wait for a standards committee to deliberate and create specifications every time some company wanted to offer another plug-in. Each flavor of digital video, every sound and audio format, even different Java apps would require a proposed syntax within the structure of HTML. Blecch....
The same would hold true of CSS without filters. Every possible visual effect - from automatic drop shadows to motion blurs and color shifts - would have to be proposed, deliberated, and specified before the design community could move forward. As we've seen with HTML, this just isn't realistic in the hyperspeed world of the Web.
So this time, Microsoft has stepped forward with both a proposal for achieving this in a standard way and an example of implementation (shipping now in Internet Explorer 4.0pr2 for Windows 95). They've proposed it to the World Wide Web Consortium as an addition to the CSS spec. You should take this as a warning: This isn't a standard, or even a recommendation for one - it's merely a proposal by one browser developer, and it could change at any time. Filter your content with care.