EasyHire.me allows you to add notes about the candidate that may not be directly linked to a particular interview session. For example, information on who referred the candidate, when is the candidate ready to join the company etc.
Click at a particular job to go the jobs page. Click the top right corner of an applicant's profile.
Select Notes from the list. This would open a panel showing all the interview notes on the candidate. Adding a new note will show up in the top with the date.