I have seen the idea of deaconesses argued on many forums, but it seems no one was ever able to define the use.
However in discussing Baptisms today, Father George explained it in a way that made perfect sense.
In the early Christian Era. Men and women were in the Catechumanate for 3 years. All the male catechumens lived with one another, as did the women in a catechumen house on the church property.
At the end of the Liturgy of the Catechumens they left and went to lessons.
When it came to baptize them, the were batized naked! (They were batized seperately)
To prevent the priest from seeing the women naked, the deaconesses would hold a sheet up over his eyes. With his hand he would push the woman's head down for the 3 'dunkings' and recite the formula while the deaconesses would assist the women getting in the water and holding the sheet up.
With this description, it made perfect sense as to why there were deaconesses and why we no longer need them today.