Great question - interesting to see the different answers.
I do matt all the ordered images that are 5x7 and up. I use foam board as a backing and cut matts myself to fit the image and then try to matt up to a standard size frame if possible.
The signing thing is something I am not very consistant about. Maybe that could be a New Years resolution. A painting I always sign but a photo traditionally has been signed on the matt. We all know those can disappear. Signing with a computer generated stamp seems so "not real" so I am hoping to hear how others sign. Signing an image on the back also does not seem to add value to the image.
I recently put a signiture on an order and not on someone elses image. The one person who did not get a signature wanted one on hers.
Speaking of signatures- I have always felt they should not be a distraction to the artwork they are on. So I place them in various places that are not really obvious. Dating the image is something to consider too. I usually do not do that either. How do others deal with dating the image?