Have others tried writing a letter to a deceased loved one?

http://www.guardian.co.uk/lifeandstyle/2011/feb/05/letter-to-my-late-son-who-had-schizophrenia

Have others tried writing a letter to a loved one who has passed on? And, if so, did it help? This is a sad letter to read, and you can only hope that the mother who wrote it has found the process therapeutic in some way.