Only stupid people who do stupid things, or allow stupid people to do stupid things on their computer should ever really need one, but it does add a level of comfort.

If someone got hacked they did one of the following:

1. Gave out thier info to a "Friend".

2. Browsed some stupid porn or warez site, or downloaded stuff that any idiot should know not to do.

3. Picked a simple password/accountname setup.

Having said that, I have one for my 5 accounts, & love it. I have my occasional moments of stupidity & this adds a little extra security.