You've written about read-only tags at RFIDJournal.com before, but I'd like to know the purposes for which I could use such tags if they come pre-encoded. What are the benefits of read-write tags over read-only tags?
Read-only tags can be used for any purpose. The only difference is these tags come pre-encoded and don't have any user memory in which you can store data. You can track items associated with the pre-encoded ID number in the same way you would track items with IDs that you encode yourself.
The main benefit of read-write tags over read-only tags is that you have more control. With read-only tags, you must maintain a database of all tag IDs, match the specific ID to a particular item, and record that association in a database. With read-write tags, you can scan a bar code on an item, use software to take its Universal Product Code (UPC), and add a serial number to create an Electronic Product Code (EPC). One challenge with read-write tags, of course, is that you must manage the serial numbers and make sure that you don't repeat any.
I hope this answers your question.
—Mark Roberti, Founder and Editor, RFID Journal