While using the facebook debugger, it complains:
Warning fb:app_id hasn\'t been included in the meta tags. Specify the app ID so that stories shared to
If you don't have an app to associate the website to, then that warning can be ignored.
For an example of a successful website which doesn't have a fb:app_id included, you can run a debug on this stackoverflow page's URL within the Facebook Object debugger, you will see that it also produces the same warning message.
The posts themselves will generally appear the same as they are represented at the bottom of the debugger tool.