From Chris Dixon’s Blog:

Network effects can be your friend or your enemy depending on whether your product has reached critical mass.  Getting to critical mass in complementary network effect markets is sometimes called overcoming the "chicken and egg problem."  Back in graduate school (2003), my friend Jeff Rhodes and I wrote a paper titled "Six Strategies for Overcoming the ‘Chicken and Egg' Problem  in Complement-Based Network Effects Markets."  This is a frequent challenge when launching technology products, yet at least at the time we had seen very few people try to systematically document strategies for overcoming it.  Some of our examples are a bit dated now, but if you are interested in this topic you might like the  full paper.