An Amanuensis is a person employed to write what another dictates or to copy what has been written by another. (As stated on GeneaBloggers ).
I am taking a smidge of a spin off this and talk about Indexing. What is it and what is its importance? Well it is all the stated above, except the paid bit ;). I volunteer, along with thousands of others, Indexing records (right now I am working on the 1940 census records) for Family Search. Anyone can participate, it is a way that I give back to the Genealogy community as well.
We read old records, supplied for us to view online through one of their programs, transcribe those records, they are sent to an arbitrator and then they are published for the public to use. My background as an RN plays a great role in this as we are made to read the absolute worst handwriting, spelling known to man. I think they do it merely to irritate those of us who are in the nursing profession! So being able to read not only present day writing, but older style writing is very important.
I do enjoy doing it, it is something I have gotten fairly sufficient at, I think in the last two weeks I have done almost 5000 names, my goal is 100,000 by the end of the year, we shall see! I would like to encourage anyone to give it a try, you can do it at your own pace, if you have trouble reading one, don't worry, it is sent to someone to proof, and you can always resubmit it for someone else to give it a shot.
The records aren't just census records, they are also tax, land records, birth, death, marriage records. If you can read other languages I know the need is great as well, they do have access to international documents that need to be indexed too.