On a number of ad-related things:
1. How many impressions in a campaign are actually seen, not just recorded?
2. Do flash display ads actually resonate more than static versions?
3. Is increased time spent within a site a good thing? Or simply a sign that your users can't find the information their looking for without searching for it?
4. That people notice online ads and choose to click on them (vs. accidentally)
5. Of how a video, any video, becomes "viral" when the original objective is to create content that becomes viral.
I've been working on a deck about metrics lately and found that even when reading a number of different articles, I have more questions than answers. Determining answers to some of the above questions over the next few years is critical - especially when it comes to the value of an impression.
More to come...