Should I use social networks besides Facebook and twitter?

[Solution]

Use wordpress platform for your site. It's good for SEO and mostly compatible with social media such as facebook or twitter. Use plugins on your site.
After that you can set automatically which posting to share on that social media. It's easy but if you want to get more specific target audience you can use this trick:

Visit and use this to grow your specific audience: http://bit.ly/1nwfrOP
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