BrowserCheck

This Firefox add-on, which also works with other browsers such as Opera, Chrome and IE8, checks your installed browser plugins for outdated versions and allows you to easily download the newer version.

This security plugin to be a mini-Secunia PSI that just checks your plugins such as Adobe Flash, Shockwave Player and Quicktime. A very useful tool to do what normally is a very annoying job.

It is here: https://browsercheck.qualys.com

Internet Explorer 9 Filters ActiveX

Microsoft's Internet Explorer 9 (IE9) allow for filtering of ActiveX controls. This should allow for much greater security from devious scripts. All you Windows XP users are out of luck as IE9 will not run on this Operating System (OS). Use Firefox, Opera or Chrome browsers for maximum security under Windows XP. If you run Windows 7 or (gasp) Windows Vista you can and should use IE9.