I already have :), but this is an interesting article:

Internet Explorer is the Swiss Cheese of software - it’s full of holes. Holes in software are never good, but when the browser is so integrated with the OS as to be as one - you’ve got problems. Add to that the sheer ubiquity of the Microsoft browser, and it’s no wonder IE has become the hackers’ No. 1 playground.

Now we’re beset by increasingly common - and dangerous - security vulnerabilities. We knew IE was integrated with Windows, but we didn’t have any idea how integrated it was. Even Microsoft doesn’t seem to have a firm grasp on IE’s internals, judging from the weeks it took to deliver an actual fix for the recent Download.Ject Trojan.

http://redmondmag.com/features/article.asp?editorialsid=439