I think this falls under "you are only as sick as your secrets" rule.
the site explains it rather well and like anything else, it depends on how it is used and what the intent and etc are.
I am pretty transparent in my relationship..but there is trust and neither of us have any interest in "snooping" or checking up because trust has not been betrayed for a month daily (as here) or months or years as some people who decide to reconcile after an affair are.
my guy isn't going to read my posts here ..altho' if he wanted to snoop, he is enough of a geek to find them..but because he trusts that if there is something he needs to know or if I have something to tell him..I will. I haven't betrayed that trust. but anyway..nah, I don't keep things password protected from him and etc. He knows my passwords. (I am more prone to mess something up on the computer and need him to fix it for me etc)