The 728x90 Expander Down ad unit is designed to attract a viewers attention by expanding the standard 728x90 ad unit into any size and shape you like.  The additional real estate provided enhances the advertiser's ability to communicate their message, while the animation event captures the viewer's attention.

The 728x90 ad unit (also sometimes referred to as a "Leaderboard" ad) is a standard position that is available on most websites.

The 300x250 Expander Left ad unit (also available as a "right" expander... depending on your page layout) is designed to attract a viewers attention by expanding the standard 300x250 ad unit into any size and shape you like.  Adding a partially transparent image to the expanded container can have a great effect as well (i.e - a car driving driving out of the ad "onto" the page).

The Wallpaper ad unit (also sometimes referred to as a "Rails" ad) is designed to take over the background layer of the web page.  While always appearing to the right and left of the page content, certain sites may also have areas (between content blocks) that display the background layer as well.  For branding impact, this ad unit leads the pack.

The Video Pencil Push ad unit (also sometimes referred to as a "Filmstrip" or "Sliding Billboard" ad) is typically positioned immediately under a website's main navigation bar.