Reposting as a new thread in case folks are interested. Many still use the barcodes for kiosk scans. Delta didn't include them on (at least some) of the 2013 luggage tags or membership cards.

If you miss your barcodes, simply visit the following website and generate your own:

http://bisqwit.iki.fi/barcode.html - Online Barcode generator

Code: (Your SM Number)
Height: 40
Scale Factor: 1.0
Barcode Type: 128-C

Then print them out, cut 'em down, and attach to the back of whatever you like. I find that clear nail polish makes a good glue and coating to make them much more durable.