Other. I wouldn't say that I'm "afraid" of someone I know following me in EF. However, that isn't something I would invite either. I value my privacy and my sexuality is my own business. Being anonymous allows me to be more honest and objective. That would be compromised if someone I knew were following me.
My friends know I'm a little off center when it comes to sex. I wouldn't like it, but I could live with my friends knowing more of the details. However, it takes more than one person to have sex, and it would be extremely disrespectful to the ones I love for those details to become known without their consent.
I wouldn't really be too worried about my friends reading my posts. I follow the philosophy that "Love is blind, friends close their eyes." My friends know that and respect that. However, not everyone is my friend.