No. My members are responsible for what they post, not me.
I've been threatened with court action 9+ times in the past five years, and none of the threats have come to anything.
I have - to the disappointment of a few a members - stepped-in to remove content when members have tried to use my site as a sound-off board for their personal grievances; but usually they have understood that my reasoning is, well, reasonable; they should not bring their personal issues to my board!!!
Same... I have had a lot of threats and a couple of attempts, all of which failed quickly, because the laws for online forums protect the owner unless the owner has knowingly breached another law, ie. copyright, trademark infringement, etc. Otherwise, many a court case already exists as precedence that the owner of the site is not responsible for what another person writes on their site, defamatory, libel, or not... the owner is not responsible for that of others.
You as the owner cannot prove or disprove whether what someone says is libel or not. Another party would have to first subpoena your data for that users details, then take that user to court, not you, for proof or otherwise of their comments, then if court ordered that you as the owner remove the content as it is proven libel or otherwise, you do so. If you didn't, then you would be breaking a law.
Until then... precedence of existing cases is quite within the owners rights and puts the onus on the user writing the words, not the site owner.
If it was the other way round, Facebook, Twitter, every forum and blog that allowed comments, wouldn't exist.
I have had only one threat of lawsuit, I was contacted by their attorney. It is kind of a sad story, once I got my own attorney they backed off, at this point I actually wanted to go to court. I contacted the other persons attorney and asked when we where going to court, he said he understood we had worked out our differences which was in no way true.
That's because his lawyer should have told him the truth... being its a no win fight. Good on your for standing up... some people fall over in compliance with a lawyer getting involved, being the purpose.
It depends if its run personally or under a company. Mine is run under a ltd company, so I have some professional indemnity to protect against any legal issues. If you go down this route, just be careful as some PI insurance put limitations or restrictions on internet forums!
Editing posts makes no difference at the end of the day, if a user posts it, you publish it - thanks to the demon Internet newsgroup case that went through a few years back - you are responsible for the content.
However, you only need to remove it if requested by the person who objects to it. Its then down to you if you want to side with the user or the complainer.
As with jonsidneyb, I've only been contacted by someone's lawyer once and in that instance, the OP was also contacted and they chose to remove the post.
I get threatened with legal action from time to time, its par for the course once the site gets big enough, imo.