Getting users 
omarchowdhury: Search marketing.This avenue may not fit your startup because no one may be searching your industry. I mean, if your startup is Twitter, you're not going to get very far bidding on the keyword "microblogging".It worked with our startup because people were already finding our competitors using search (our competitors literally created the search market for us because of their large scale media buys offline), and the volume allows us to scale.