Depends on the Market and Industry. Some industries definitely benefits to release teasers, whitepaper, Ads, & begin stimulating demand in chosen market. But I think the product must be in production before stimulating. I would make sure the product has met every expectation and can be easily replicated in Factory. A good Example is PUNDI-X in Cryptocurrency. They shilled the theory & wallets long before the released their XPOS system to the public. However they did have a few 1000 XPOS ready to go before their Blockchain payment system went live. Slowly they are converting from ERC-20 token setup to their FX chain. Now with FX live & BTC being adopted as a National currency in multiple countries that the XPOS offered by PundiX & FX project will be exploding as more countries adopt BTC as a legit currency. Only company with a Real HARDWARE XPOS that can process any credit card and nearly any major altcoin in existence. They knew that Crypto would be adopted at government level eventually & PundiX postioned themselves to break out between 2021 & 2024. Come 2024 we could see a $50 dollar Pundi-X 7 $50 dollar FX coin. IN the crypto community ICO's(Initial coin Offerings, always stimulate demand a few months before they launch their sale. ) So when it comes to startups, without any merchandise like most ICO's who are just code & Whitepaper with Roadmap. Take XYO for example. They MAXIMIZED their Audience by using Social media and even though they have yet to meet many of their RoadMap bullet points, they were still able to generate considerable demand & massive following long before a single piece of the XY persistent company, or XYO Coin apps went live. So when it comes to creating a marketplace, it always depends on the industry.