Data Transfer is the amount of data transmitted over an Internet connection in a given time. It is used up by traffic to your Web site and also sending and receiving e-mail. For example if someone views a 1MB Web page on your site 1MB of data transfer is used. If 10 people view it then 10MB of transfer will be consumed. If you send an e-mail with a 2MB attachment it will use 2MB of data transfer. The amount of transfer that you require while choosing a host depends on two factors:
1. The size of your site and
2. The popularity of your site.
If your Web site provides large audio/video files, computer
programs, and audio / video downloads then you should consider a
package with a large amount of data transfer. For example, if you have
a video file that is 1.5 MB in size and 100 visitors download the file
during one day. This means that 1.5 GB (1.5MB * 100 visitors) of
transfer will have been used. If you multiply that by 30 days for the
month it comes to 45 GB.
Flash Web sites and Virtual Reality (VR) sites require the most transfer of all.