Yep! Social media is a great tool for digital marketing. And by advertising bitcoins you make more people invest in it, so in that way it has influence on bitcoin growth 
I agree with you buddy, Social Medias now a day is the best way of advertising products, item, idea, and knowledge such as bitcoin.
Because almost 89 percent of people are using the internet to spend their leisure times, past times and they read also some news or updates on online social medias...