Some time last year, this had happened then as well.
What did Microsoft say?
"It's only one vulnerability."
Well, here's another; many also believe that there are many, many more vulnerabilities waiting to be discovered in Internet Explorer.
And due to the proprietary nature of the code, they're all going to be found the hard way -- by people getting their systems hacked. Don't be one of them.
Looking to ditch IE? There's lots of more secure alternatives, namely:
- Firefox 3.6
- Google Chrome
There's some more as well, but those are the larger and more notable of the browsers.