[balazsdavid987]

I think that is absolutely doable but efficiency depends on the product/service. Start a blog, write about the problem you solve and post it to HN, reddit, and other sites but do not spam, make sure you provide value. You either spend money on ads or you spend time on creating content. Just creating the product, putting it online, and waiting for users to come simply will not work.

[Huhty]

You can also use previously written blog posts and link to them in comments areas (discussions) when relevant. The more things you have written about, the more appropriate situations you will find yourself in to link to them, as long as you are active and attentive for the right opportunities.