It’s just some animated gif images, stored in my Dropbox cloud space.
After saving my screencast as avi file, I convert it to animated gif image via Format Factory.
Then, put gif image in the “Public” folder of your Dropbox, right click and you will get the direct link which you could use in the forum.
Because of my poor English, I use these animated screencasts to help me explain ideas or problems. 😛