Interstitial

An Interstitial is a web advertisement that appears on its own page, typically in between "content" pages. Interstitials are typically not clickable (or are linked to the page you'd originally hoped to reach), but are usually buffered by a similar, smaller advertisement on the subsequent content page that allows you to investigate the advertiser's product. By mid-1997, interstitials were at the top of every advertiser's want list, but have lost popularity since then.