We need 100 supporters to start a #standup4girls social media thunderclap.

What is Thunderclap? It is an app that allows organizations and their supporters to share a message on social media (Twitter, Facebook or Tumblr) in unison at the same time, automatically.

That means that if you pledge your support, the Thunderclap app will automatially post our #standup4girls message at 12pm EST on the October 11th International Day of the Girl.

How do you sign up to add your support?

It's easy.

1. Click here to visit our #standup4girls page on the Thunderclap website: http://thndr.it/19FxqXx

2. Choose which of your social media sites - Facebook, Twitter or Tumblr - that you'd like to use to share the message and click the button that says "Add My Support."

3. A "Thunderclap Preview" window will pop up. Click the "Add My Support."

4. A window will open asking you to authorize the Thunderclap app for your Facebook, Twitter or Tumblr account. This window will also ask you to log in to your account in order to complete authorization.

5. You're done! The #standup4girls message will be posted along with our other supporters at 12pm EST on October 11th. Thank you for joining us to speak out and Stand UP for girls' stories.