I guess it depends. A counter example would be the kind of grassroots organization Mozemo from Croatia whose candidate recently was elected the mayor of Zagreb,

I guess it depends. A counter example would be the kind of grassroots organization Mozemo from Croatia whose candidate recently was elected the mayor of Zagreb, and they hold almost the majority in the city hall (which is difficult for a single party as there are many parties).They also did well in multiple cities. I checked their Twitter a while back, and they only had about 6k followers. On Facebook, they have 50k likes, but this is in general not a lot since they were a major regional story. I wouldn't be surprised if half of those likes came from outside the country. I don't think their good result is really powered by social media. So I don't think communicating with voters is a solved problem, and I don't think Facebook / social media is the only channel you have. It's important maybe, but I'm not sure if it's definitely "essential".