What is the best tool for social media marketing? and how to create a backup if the social media marketing fails?

I have been a great advocate of Buffer. It allows you to schedule posts and also sift through specially curated content. If you have a premium account, you can also set multiple feeds based on your interest. The content of these feeds can be scheduled for Twitter/FB/Google Plus/Linkedin with a single click. They also have an extremely smooth app for mobile use.

Hi man isn't than question of the year.
There is nothing as Best Social Media Marketing Tool.
Let us sat I brought to you a Ferrari and you are living in Imbaba, what will happen to it? It does not matter how good is your tool if you do not know the reason behind it.
However, you can start categorizing the tools by job (measurement, automation, analysis, etc), price, or channel as a start.
Try these also to widen the view:
1- http://www.grosocial.com/
2- or check Wikipedia http://en.wikipedia.org/wiki/Social_media_marketing#Social_media_marketing_tools