Yes and No.

NO

because JMS only share the files and folders present on the disk. It shares the Joomla Installation.

The each websites used its own content or at least different table prefix when it shares the same database.

This means that articles, news, forum, users or whatever that is stored in the database is totally independent.

YES

because we have developped a special component Articles Sharing for Joomla Multi Sites that allow to display the articles, categories, sections from any websites defined with Joomla Multi Sites.
With this extensin, you don't need anymore to replicate or use special extension to synchronise the websites.

This “Articles Sharing” consists in a new menu type “Multi Sites articles sharing” that works like the standard Joomla menu type “Articles” except it adds the possibility to select the websites where the articles, categories, or sections are located.
Articles Sharing for Joomla Multi Sites only display the articles.
The menu type implemented are:
-    Multi Sites articles layout;
-    Multi Sites Category Blog Layout;
-    Multi Sites Category List Layout;
-    Multi Sites Front Page Blog Layout;
-    Multi Sites Section Blog Layout;
-    Multi Sites Sections Layout;
It does not allow to edit or submit articles.
“Archives” is not implemented.

The articles sharing required with JMS 1.1.5 or higher.