what do you mean big number?you can get organic traffic from google after some seo work,that is time consuming,or you can get traffic from youtube,facebook,twitter, forums etc,or you can advertise with adwords
SEO isn't what you should be concerntrating on. SEO is only good if you have amazing content that people want to read. Whats the point in optimising something when the audience will read it for 5 seconds? If you have interesting and appealing content they will stay and spread the word.Make a campaign? (Get a friend to join and make 50 posts and earn $1) or something silly. You will get views etc and people will give feedback.SEO is a last step.
Lots of high quality unique content will bring you organic traffic, the more high quality content the better.