Poynter discusses an interesting dilemma the Ventura County Star had to deal with. A woman revealed the name of a possible murderer in a comment on a newspaper article published online before the paper had confirmation that this person really was the murderer. I see no reason why they should have removed the comment (and they didn't), as long as it is clear to readers that this was a comment from another reader.
"Moore traded e-mails with the woman and found that she had been following the case closely and had heard enough clues to enable her to do some Internet sleuthing -- using freely accessible websites and databases -- and figure out the suspect's name in about 20 minutes. Unbound by traditional journalism rules like making sure she was right, she posted the name."