Data transfer allowance refers to the amount of data that can been sent from server to the client or vice versa under your chosen hosting package.  For example, if your hosting package's data transfer allowance is 5 Gb / month then you can transfer up to 5 Gb of data.

Everytime a visitor views a page of your website the data is transferred from the Server to the user via the users web browser. For example, a page with only a few small graphics (Jpegs, etc) may require the transfer of around 50KB of data, whereas a large image or multimedia file would require much more - perhaps Mb's of data. You should note that email and data transfer are also added to your monthly data transfer.

If your data transfer is nearing the limit of your chosen hosting account. you will receive automated warnings from your cPanel advising you of the need to take action (such as contacting us for an account upgrade).  If you take no action and your monthly transfer allowance is exceeded, then your account will be suspended until the 1st of the next month.