I have taken the title of this post from a post by Susan Heathfield on About.com.  You can read the post here.  I agree with the whole of this post and it is a great summary of what can go well with 360 degree feedback and what can go wrong.

By avoiding the "bad and ugly" of the third page of Susan's post you would go a long way to a successful 360 feedback implementation.

I also like the reference to managing people through pointing out what they are good at, rather than focusing on weaknesses.  Those of us who have "taught" a child to ride a bike will know that it is a fruitless exercise to repeatedly tell the child what they are doing wrong.  The challenge they face is they have no experience or knowledge of what the correct way of riding the bike is.  So, encouraging them when they remember to put their feet down after they have stopped rather than telling them the problem with putting feet down early works a lot better. And "go faster" and "stop wobbling" doesn't help them at all!

The output from 360 or from performance appraisal can too often be viewed as highlighting weaknesses.  Most of us are as much in need of being told what we are doing right - so we can repeat it and enhance it - than of being told where we are going wrong.

Brendan