Adding your site doesn't cost a thing. We would prefer if you add the code that links to us, but don't insist upon it (code will be emailed to you upon registering). To encourage you to link to us the ranking is calculated as follows:
1. (In Clicks x 3) + (Out Clicks x 2) = Rank
2. Traffic (Unique Visitors) to your site = Rank
SciFi Topsites resets stats daily so everyone has a chance to reach a higher rank.