I have just read Dan Parvaz's contribution to the discussion on signwriting as a writing system. I hope Dan doesn't mind me saying that would not push aside the great developments that can be partly or fully attributed to the alphabetic invention. They are many.
Nevertheless, one should keep in mind the fact that if no language had yet been written and we were about to start now, it would be preferable to use a system similar to the IPA (International Phonetic Alphabet). However, at this point in time it would not be worth while changing all orthographies based on the alphabet into the IPA system (I would need a few weeks to explain why...). BUT since we are just starting (more or less "just" starting - apologies to those under 30 or so !) to write sign languages, then it is wonderful to find a system that is "phonetic" to a greater or lesser extent.
This same system, i.e Sutton Signwriting System, can easily be used "phonemically" once the writer (previously transcriber) gets used to the system. At that stage he or she will become a writer using what we could call a shallow orthographic system (meaning more like Spanish than like English).
The advantages are many: it is easy to learn.. Once you know signwriting, you can signwrite any sign - even an unacceptable (e.g.morphologically unacceptable etc). This is necessary when using signwriting in a document discussing a sign language, for example. So this makes it possible to follow a sign language in terms of the identification of what you would see if the signer were there but you can gradually start to omit the redundant details (the more phonetic ones) and hence the speed can increase. I am sure Valerie explained that some time ago (apologies for my memory as to when and in what context Valerie!)
You may hear from my colleague, Maria Azzopardi, very soon. She could tell you how (and how much) she is using signwriting. Later on we will send the sw-list details on our work on a dictionary for LSM (Maltese Sign Language) using signwriting.
I apologize for my over-lengthy contribution to the discussion. As a linguist I couldn't resist. I would say that SW is an extremely useful tool for researches too.
Marie Alexander - from the middle of the mediterranean...!!!