Joomla multisite itself does not share the content of the database between the websites.
See FAQ
www.jms2win.com/faq#sec-72.
We have developped a specific extension "Article Sharing for JMS" that allow display articles coming from any website defined in JMS.
See
www.jms2win.com/download?page=shop.produ...34&category_id=1
With the article sharing, you can for example ask in a slave site to display a category present in the master website or in any website.
Imagine that you have a corporate with different branches and that you want create several website for the different branches but also display articles coming from the head office. You can create a special category in the head office website where you will put all the articles that you want display in the branches website.
In the branches website, you will just have to define a menu item that display a blog or list category coming from head office website.
The article sharing component is able to read any articles defined in any DB associated to the JMS site identifier. The article will be displayed using the themes (template) of the slave site. Therefore a same article can have different layout depending on the slave site where it is displayed.
For the moment, only the "Article Sharing" component exisits.
I have not yet developped an equivalent for the news or other joomla component.
In JMS 1.2.x that will coming soon (in few weeks), it will also be possible to share some extension and in particular the Joomla users, VirtueMart user, all VirtueMart, Community Builder and perhaps other extensions.
This new sharing feature in JMS will require MySQL 5.1.2 or higher.