Friends come to the sites you create to connect and be entertained, regardless of value of content.  Random people visit the sites you create because of the information that you write about better than most others on a given subject.  I recently remembered to seek out the answer to "why do random people stuble upon my sites?"

Google Webmaster tools are easy, free, and answer this question.  Here are the keywords that generated visitors to this site.  Interpretation: Guatemalan Orphans are a hot topic and a big reason people value me.