As soon as it's information found by going out of your way, you're crossing a line.
In many cases, if you dig a little, you're going to find something that bothers you. You dig into their past sex life, chances are, something's going to upset you.
You go and start looking up posts online, odds are, you're going to be disappointed.
ANYTHING beyond what they do with you, or for the couple, is across the little privacy line. Keep in mind, the trust line is something else.
If you choose to step over that line, and look at what they're doing, you're just ASKING for disappointment.