Platform, platform, platform. It can be fun or a huge waste of time depending on who you talk to these days.
Generally publishers want to see that authors have some type of social media presence. This is because they want to know that authors are engaged at some level with potential readers.
Does a huge following help? Yes. Is it necessary? Not at all. A few hundred followers on a blog or social media page are enough to show that you’re out there. Anything more is really just frosting on the cake.
Keep this in mind as you manage your time. Never allow a quest for big numbers to take time away from your primary goal, writing.