Recently I encountered a problem where by I could not see the ‘Posts’ tab on the new activity feeds for out the box entities like Account and Contact. The issue only seemed to occur for my organisations that had been converted from MSCRM 2011 to MSCRM 2013. For any new organisations that I created on 2013 the ‘Posts’ tab was visible. What appears to have occurred during the upgrade process is that I didn’t receive any changes to the sitemap. This meant that I could not see the new CRM 2013 sitemap items like the ‘Whats New’ Activity dashboard, but more importantly I could not see Post Configuration which should be accessible from the Settings. It is within Post Configurations that you can activate posts for given entities. In my case all entities had posts deactivated apart from user. To activate posts and therefor make CRM render the posts tab follow the instructions below.