These adverts are displayed on screen before the user is allowed access to the actual website content they came for.
Interstitial advertisements are often used on news based websites are controlled on a “pay per display” system, instead of a “pay per click” system such as Google Adwords.
The common “skip-over” mechanism in interstitial advertising such as “Continue to the Site” for me is actually a satisfying experience of denying that ad any more screen time, yet there are some that don’t allow that redirection option.
The idea of denying a visitor the option to opt out of these advertisements is playing a key role in advertisers willingness to use “interstitial advertisements”.