Anonymous Commenting Disabled
I've been fighting against doing this for a number of months, but we have had to disable anonymous commenting due to recent attacks on the site - specifically in the form of flooding out comments with attack pieces including posting photos of bowls of human feces (left up only as an example for why anonymous commenting had to be removed).
In any event, anonymous users must register to post comments, all it takes is an email address. On a side note, the poll which was run last month ended up with 5x more users wanting to remove anonymous commenting than continue to allow them.
Making this change is not something I wanted to do, but unfortunately there are those whose focus is on anything but being constructive.