For example, using this exploit you can be tricked into turning on your web cam, or installing malware. All browsers are vulnerable to this type of threat, so this is not just isolated to I.E., Firefox, etc.
The way the attack works is you go to a site that has been modified by a malicious attacker, then the content (i.e.: web pages, flash animation, etc.) of the site tries to trick you into clicking links and buttons that you might not realize you're clicking. They do this by disguising the content to look like something else.
To help protect you, here are some resources:
- For Internet Explorer, under Internet Options... in the Security tab you can set the Internet security slider to high. This should block all scripting technologies from running on any web pages you visit. If you want grant permissions to specific web site, you need to add them to your Trusted Site list.