As online advertising spend increases and agencies clamour for access to more retinal real estate, the Interactive Advertising Bureau (IAB) this week launched six new advertising formats at the online world. Proposed by agencies in a competition, reined in by publishers and other agencies on the judging panel, the new formats promise advertisers access to as much 950x550 pixels of the browser window (read: all).

It’s more subtle than I’m making out. Genex’s nearly full-screen ad format, Slider, is accessed by clicking a bottom-of-the-page full-width banner, sliding the main content of the page off to the left, revealing a branded site-within-a-site.

The other winners include:

• YouTube’s 970x250 Billboard, viewable now on their home page
• AOL’s 270x1050 Portrait, nearly a website in itself, but relatively inflexible for its rigid modularity
• Pictela’s Pushdown, a 970x90 banner that pushes a page’s content down to expand to 950x415
• Unicast’s Sidekick, a 300x250 ad expanding to 850x700, and
• Microsoft’s 300x3000 Filmstrip

On first look, MS’s vertical-scrolling Filmstrip carries the most potential for publishers, in print and online, offering almost a million pixels of billable branding without carrying the user away from their editorial content. And for touch-screen initiated readers, this seems a promising format for scrolling excerpts, tube links and other promotional goodies.

What do you think?