Not only was the content morally questionable, it could have serious consequences for those who claimed to have committed a crime under the veil of anonymity.
"It depends what their postings are but particularly we are concerned with anything detailing crime or anything sexually explicit," police spokeswoman Kris McGehan said.
"We are monitoring the site and we do have the ability to track these people down.
"Whether they would be charged depends on tracking the person down, and finding out if what they have said is true."
Police were in no way bound by the Privacy Act when tracking crime on websites such as Facebook.
Though the sites had offended many people, with Netsafe New Zealand aware of a number of complaints, they could be hard to remove.
"We can work with Facebook or other social networking sites to get something shut down, but it can be a very difficult process."
Hawke's Bay Police recommend people choose their words wisely, when it comes to telling all.
"We would certainly urge caution for people about what they post. There is the possibility of criminal investigation so be very careful what you say."
Even when the pages were taken down, there was no guarantee posts would disappear forever, executive director of Netsafe Martin Cocker said.
"If a page is deleted it remains on the Facebook system for a period of days before it's properly deleted, but the thing is if someone else has linked to the page Facebook can not delete it."
While page administrators promised "100 per cent" anonymity, it may not stay that way, he said.
"I think the thing is, people assume they are protected by anonymity, but you can't guarantee they will remain anonymous into the future, when you are not in control of the site."
The creator of OMG Confessions (Hawke's Bay), who declined to be named, said the page was created out of "boredom" and was harmless.
"To be honest all I have to say is that it's not hurting anyone as it is anonymous," they said. "If there is a problem, it's as simple as unliking the page or just not opening it to begin with."
When asked about the threat of legal action or criminal charges, they said: "I have stated that nothing is to be mentioned of rape etc as it will not be posted and the page is not here for that.
"If you have something to get off your chest or need help on something then it is easily and anonymously done. I am simply the copy and paste person in the middle."
The creator said their page was "far far more dialled down" than the other page, and that some of the confessions were simply untrue.
"The legit messages that I have been sent to post up anonymously have been done to gain feedback on a situation or problem that they would otherwise be too scared to find the information for or talk to someone personally about.
"And as for the other posts, it's always good to have a laugh every now and then."
They said people who disliked the content should not join the group because, "if you don't like a movie that's playing at the cinemas, you're not exactly going to go and watch it now are you?"
Michael Wrigley, a solicitor specialising in internet law, said there could be consequences for the facilitator of a page such as OMG Confessions (Hawke's Bay).
It was the administrator of the page who would come under fire for publishing defamatory information on the site, he said.
"The administrator is even more exposed.
"If you look at a newspaper, the people who are liable for defamation are the journalist, the editor and the publisher.
"There is a question mark over whether the news agent and the person delivering the newspaper are liable.
"Everybody in the chain may be liable. In my view Facebook is liable in cases like this one."
Mr Wrigley compared the facilitator to a newspaper editor publishing a defamatory letter.
"The person running the site is probably based in New Zealand so it's easier to sue. For instance if I was acting for the mayor and I was really annoyed I could write to Facebook asking them to disclose who the person is and they would have to disclose all of the emails and communication they had received.
"Under privacy legislation, there are exceptions. You can get an order to disclose who posted the comments."