I'm on another advertising network that requires all ads "above the fold." However they won't define in precise terms what "above the fold" really means. There are two important considerations I can think of:
1) Screen resolution. I use 1024x768 but most people I work with use 1280x1024. So an ad that dips below the fold on my screen could be entirely above the fold on theirs. So I wonder what is the standard resolution used to define "above the fold."
2) Toolbars - some people have as much real estate dedicated to toolbars as the browser area. So I wonder how many toolbars are used when defining "above the fold."
The difference is huge. An ad may easily appear above the fold at 1280x1024 with no toolbars, yet be buried at 1024x768 with 3 or 4 toolbars.