Wow...altering PMs'? I didn't even think that was possible. That is crazy if that happened.
Writing as someone who hosts forums.
Everything in a forum will be held in a database. Even if the forum software itself gives you no access to other people's PMs (I know of none that actually does), it is fairly trivial to access them directly via the database. Changing or deleting data is equally easy.
However, it seems strange that someone would have the level of knowledge to do this, and yet be unable to fix a broken forum, taking it offline for several months.
I hasten to add that although doing all of of this is easy for anyone with a technical bent, I would never dream of doing it on any of my forums. If you don't have trust, you have nothing.
I believe you are alluding to this:
Being a data base, I would think any program that could access that data base would have the capability to "find and replace" certain words. I have no familiarity with whatever PM transgressions happened at PH but if it was something like replacing "pelletfan.com" with "other site" and it affected the entire site, I would have no issue with it whatsoever, especially if the words they are replacing are a link to a competing site. If I felt the moderators were reading through my PMs specifically I'd probably be more offended but I never considered "private messages" actually private from those that manage the site.
I was merely commenting that it is possible, even easy, for an admin (not a moderator) to read and edit all PMs; in response to the comment "I didn't even think that was possible."
I was not suggesting that had happened at the site in question, because I don't know; and - as I say - it doesn't fit with the technical expertise we have seen there.
As such, I wasn't alluding to nothing. I was making a statement of fact, that forum admins can trivially have access to everything, even if they don't exercise this.
It would be possible to design a forum where the texts of PMs were at least encrypted in the database, rather than being held as clear text. To the best of my knowledge, no forum has this as a feature. It still wouldn't stop a determined snooper with admin privaleges, as they would also have access to the encryption key, but it would make it a lot less convenient for them.