How to Tell if a Product is Hot or Not: User Engagement Activities?

Doing Market Research with GitHub

A few years back, Big Data was very hot but now it is not. Artificial Intelligence is now the darling of the world. How many startup companies have jumped onto the Big Data bandwagon and not making any money at all? So what happened to all those glowing market research reports on Big Data?

How do you find out what is really hot before jumping into the fray? We need to do our own assessment.