Why you need strong authentication wiki

I have come across a number of sites across the Internet that discuss why strong authentication is a good idea and many go into good detail (such as http://mongers.org/authentication , but I haven't ever seen a broad discussion of the reasons why in one place.

As noted in the previous post, you get a lot of benefits by deploying two-factor authentication, but what are they?

I figured the best way to get a comprehensive analysis was to create a Wiki and let the good folks of the Internet do the work for me. I have gotten it off to a start, but I'm sure there is plenty to add.

Presenting the The Why You Need Strong Authentication wiki. Please contribute! (and let me know if there are problems ;)