Last month's shootings in Arizona that wounded Rep. Gabrielle Giffords and a dozen others, as well as killed six, has sparked lots of talk in the media industry about correcting erroneous Twitter posts. NPR reported early in the shootings that Giffords had been killed.
When you have a minute, scroll through this replay of a Poynter chat about what a Twitter corrections tool might look like. The replay is free.
Also, read in your 2011 GateHouse Media Newsroom Handbooks -- and at this link -- about the ethics of correcting errors in user-generated content and comments.
Long story short, correcting misinformation on all platforms is a must. Know what your policies are now, and if you don't have any, start here.