In today's marketing world Content is king and if your website have unique content and you are publishing blogs, article and press releases with unique and attractive content then obviously your ranking will be improve. On the other hand use social media websites to increase traffic on your website.
There are lots of social media website but it depends on your business, what type product you have and services you are giving. If your targeting local business then your first priority should be local social media websites and if you targeting global market then your priority will be website...