I remember when I built my own social network as well (www.thecaucus.net). The core feature was fancy algorithms similar to pagerank, that calculated a score for each post. This is in contrast to Reddit where the score is directly proportional to the number of people who liked it. I posted a link to it on HN, and got angrily chewed out by someone for misleading people about the number of people using my site. I wonder what they would make out of Reddit literally flooding their site with fake accounts.