Facebook experts ... non-friend of a friend and comments on ... ok let me explain?

[Eloise]

I have a friend "sara" and I commented on her (friends-only) post.

Then I got a notification that "jane" also commented on sara's post.

I click on "jane's" profile, (who I am not friends with), and "sara" is not a mutual friend .......

how is this?? doesn't this mean that jane and sara are not friends? so how did she comment on a friends-only post?
no tagging. just a simple "good night" type of post.

[Icecream]

Maybe jane's friends with someone who is tagged in the post?

[Don]

i have not got the this kind of the problem in my facebook account.I have always used the facebook account .I was very happy to used the facebook account.

[Claire]

If you cannot see ‘Sara’s’ name in ‘Jane’s’ profile as a common friends, then they are definitely not friends. I think the security setting of ‘Sara’s’ post is ‘Friends of Friends’ and not just ‘Only Friends’. I can’t think of any other possible explanation for this situation.

[abraXus]

the ticker shares more than you realize

read this

http://abrax.us/Facebook/PrivateTicker.php