Browser "Safe Site" Plugins

Jason Lam's recent ISC diary post about WOT reminded me that we haven't reviewed browser security plugins for site recommendations recently. There are at least twoo browser plugins that can be useful for less savvy users when browsing the Internet, including:

• WOT
• McAfee's Site Advisor

BlueCoat's K9 is a bit different and provides features including activity reporting, safe search enforcement, time restrictions, and many other features more appropriate to a parental controls environment.

What browser plugins do you recommend to your non-technical users?