Retain 3.x, 4.x
Why are there BLOBs in the notify directory?
When a user exports and downloads a PDF from the Retain web mailbox there are temporary files that need to be made to create the entire PDF. These are stored in the ~/archive/notify directory.
If this directory becomes large it is allowable to delete old items from the directory. You would want to leave any from the current date as the user may not have saved the file to disk yet.