The Community Site is a new template in SharePoint 2013 that allows us manage discussions and Q&A contents in a comfortable way. Unfortunately this template is not available for creation as a subsite (in the browser) of a Publishing Site – even if you add it to “Page Layouts and site templates”:

Add subsite shows the following (I added “Team Site” just to make sure that the “Collaboration” tab is showing up):

Activating the feature “SocialSite” does the trick:

enable-spfeature -Identity 4326e7fc-f35a-4b0f-927c-36264b0a4cf0 -Url <site collection>

Now you will be able to create a Community Site as subsite of a Publishing Site:

Markus