By default, announcements are not available for the user in versions > 2011.
In Settings –> Announcements, it is still possible to configure them.
To show them in the basic navigation, you have to manipulate the SiteMap. I suggest to use XrmToolbox (SiteMap Editor).
You can also add the XML-Code manually.
1 <Group Id="MyWork" ResourceId="Group_MyWork"...>
2 ...
3 <SubArea Entity="businessunitnewsarticle"
4 Id="nav_news" Url="/home/homepage/home_news.aspx"
5 AvailableOffline="false" PassParams="false" />
6 </Group>
Cheers
