Is there anything wrong with seeking revenge?

Are revenge and justice one in the same? Should they be?

I see a lot of comments on social media today, regarding the events in Boston, suggesting that when they find the person(s) who did this that we ought to “string them up with piano wire” and we need to “bring back public execution.”

In a lot of high profile cases I notice people wishing torture, rape and death upon the convicted.

Is violence a solution against violence? Does it say anything about our culture (and/or humanity) that we embrace violence or death, as long as we feel it’s justified?