"The two new formats include one in which an ad that appears either before or after a video contains a cue for the viewer to mouse-over the video window. Doing so displays a message in a semi-transparent overlay on the video ad. The message prompts the viewer to click through to the advertiser's site for more information.Along with the above "clickable" ad, Yahoo introduced a three-second splash ad that appears when a video is launched, but then becomes a banner ad above the video window. When clicked, the banner pauses the playing video and launches an interactive ad.
Yahoo has made the new ad formats available in the United States on all videos across the portal's network. Companies that have used the formats include Adobe, Esurance, HBO, and Sharp."