Adding new option in sharepoint 2010 site actions

I am working on sharepoint server 2010. I want to add an option to

Site Librart Tools ribbon Documents Share & Track

By default a link called "E-mail a Link".

How can i add custom link by us开发者_如何学Cing feature enabling programatically.....?

You need to deploy a feature with a CustomAction element. There is a full example on MSDN at http://msdn.microsoft.com/en-us/library/ff407221.aspx