I think that there are a couple of factors you are omitting from your analysis.<p>First, if you take a look at Dave McClure's AARRR model (and if you haven't, you really should [1]), you realize that Referral is something that you only want to attempt after you've got ridiculously satisfied customers. You can't expect people to spontaneously recommend your product on to others until it is absolutely friction-free, and serving that sweet spot so sweetly that they almost can't help it.<p>Second: not all niches are created equal. Are folks whose itch is scratched by your particular product significantly more likely to be in touch with others having the same itch? For some niches, yes. For others, no.<p>Finally, in the absence of a Freemium model, you definitely need to have a well-organized Activation process; some way for people to get engaged with the product prior to a commitment.<p>[1] <a href="http://500hats.typepad.com/500blogs/2007/09/startup-metrics.html" rel="nofollow">http://500hats.typepad.com/500blogs/2007/09/startup-metrics....</a>, for example.