If I am not "friends" with someone, how is it possible to comment on their posts?

I did not think it was possible to post a comment on someone's post if you were not their friend, but "comment" and "like" is enabled when I look at a certain profile of a person who, like I said, is not my fb friend.
Asked Jun 15, 2010
Just click on their facebook and send a message.
Answered Jun 16, 2010

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