As with 2012, 1996 and 1992 we have an incumbent. This means that the other party knows who they are going to be running against, for the entire 4 years prior. President Trump can speculate, but does not truly know who he will be running against in 2020.
Social media has evolved like never before, so it will be buzzing alive with political information, until election night. As far back as 1996, the Internet was popularized to the mainstream, and had plenty of sites speaking about the election, but the social media (that I may prefer to call autonomous subsets) had not evolved into being yet. Information wasn't organized as well.