To get traffic on your site social media is very effective. Like facebook, twitter etc. Use social bookmarking like reddit, stumbleupon, digg and you can do blogs, articles, forums for getting traffic.
The sources mentioned by you not doubt helps to increase the traffic of the website, but not necessary all the technique will work for niche. Now SEO is all about Content Marketing, so one should focus more on creating quality content and driving traffic by sharing content in social media sites.