For the sake of this post, please make sure you read minimum viable test vs minimum viable product post.
You must plan marketing before you launch your minimum viable product. If you don’t have a blog and other inbound channels while you are planning to launch your product, you will probably depend on a techcrunch article, hoping your product goes viral on HN or Reddit, and expensive pay per click advertising.
The free channels of inbound marketing take time and patience to work. If you start early, you will be much more likely to have effective inbound marketing by the time your product launches.
A common complaint about marketing early is that a team doesn’t have a product yet, so why should they start marketing? They don’t even know what their product will be.
My Response – blogging is easy, and there’s no better time to blog than customer development when ideas and knowledge is flowing. You should have tons of ideas for blogs. You will be learning things everyday when you talk to new people. You will have plenty of things to talk about. Start blogging when you start looking for your minimum feature set. If you do this, You will have organic traffic before your product launches.