I spent two thousand dollars on adwords and got zero sign ups. I did this pretty much to A/B test two landing pages, obviously I couldn't get any useful data of it because no one signed up. Also, it was my intention to get a couple of users help us improve the app.
Even though I founded a startup before, it wasn't a web app and we physically reached potential customers. That said, how does a web startup can get someone to signup without reaching to them individually?