Screencasts are a great idea. They are a really useful aid to training and education, and I think there is a big role for them to place in libraries communicating with their users. But... I am not a natural born screencaster.
Here's what I came up with on ScreenCast-O-Matic:
It's dreadful, really. What I'm trying to inform you of is pretty useful I think. But the way I've done it is appalling! I think I could do better with a program that enabled me to edit, and a bigger mouse-mat (I could never get the cursor where I needed to go in just one smooth move!); however, the fact that most other people managed something pretty decent (I'm thinking particularly of Gareth's fab video, with music!), persuades me that I am not naturally gifted in this area...
For some eloquent, simple instructions on how to do what I attempt to show in my video (subscribe to an RSS feed of new items by subject heading), see Rachel Marshes notes on the UL Service Development Blog (Raven ID required)!