#! In a URL, what does it mean? [duplicate]

This question already has answers here: 开发者_如何学运维 Closed 12 years ago.

Possible Duplicate:

What's the shebang (#!) in Facebook and new Twitter URLs for?

#! What does it mean in a URL ? I found it in facebook & twitter url !

http://www.facebook.com/#!/

http://www.facebook.com/#!/?sk=messages

http://www.facebook.com/#!/?sk=ff&ap=1

http://twitter.com/#!/messages

http://twitter.com/#!/BillGates

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This is called the shebang URL hash, used to hint to search engines that this site is using Ajax to display another page.

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It is meant for AJAX and Google indexing.