Do what you need to do. When I REALLY want to vent (I'm talking about rude, childish name calling kind of venting), I write in my paper journal. Because too many times I've seen people who post thing public when they meant to click "private". A former best friend of mind made that mistake once. The post was only visible for 20 minutes but when I commented on why she thought I was bitch, what did I do?, she immediately locked it.

Sadly, there is no such thing as a Safe 'Net. I go by the rule if I don't feel comfortable in people knowing it, no matter how secure the filters might be, I don't post it. I write it.