Which data sets would help to predict (exponential) market trends?
From a quick look, my guess would be that maybe they mine data from some predefined target websites, typically social media: twitter, facebook, etc. I could imagine that they capture trends in the sense of &quot;what people are talking about&quot; on social media platforms, but maybe they have other sources and methods.
There are Natural Language Processing methods which can be used: the basis would be some form of topic modelling, then there could be some more specific applications such as event detection. We can't know how much manual post-processing is involved though, there could be a manual filtering to remove irrelevant stuff.