Our website is built on the Concrete5 platform. Is CiviCRM compatible with Concrete5?
Perhaps it isn't as clearly documented as would be expected (seeing nothing on front page or /about or /get-started actually talks about CMS) but nevertheless CiviCRM has been built to work with Drupal, Joomla! and WordPress. Hence the answer is somewhere between 'no' and 'incredibly unlikely' ;-)