Ok, to all the haters - lets discuss this sensibly for once
Ok, lets start with a simple agreement - all commercial sites need to run display ads to survive (even the mighty Reg).
Next, advertisers demand animation. Outside of Google Adwords this is non-negotiable. It's a brand building exersise, and static / text ads ain't gonna cut it.
So, lets kill Flash because Steve says so. Now what? Two options:
1) Have animated ads that run 30fps video in an HTML5 container.
Pros: No Flash.
- Massive bandwidth consumption (min 1MB per 15 sec ad)
- Massive CPU usage once you've got 2, 3 or 4 of these running on a page.
- AdBlock now needs to disable the HTML5 video element, so we're back to where we started.
Pros: No Flash.
- Hugely inefficient as the client runtime libraries (that were a one-time, 1MB download from Adobe) are now using different technologies (JQuery, YUI, etc) and having to download those for every ad view on every page.
- The optimisations are less efficient (e.g. you need to deliver a PNG24 to do Alpha transparency, whereas you can give a JPEG alpha trasparency in Flash).
- There's no potential for efficiency through compiled code or hardware acceleration -- every frame of movement is being calculated from complex math functions and rendered at runtime (This is a huge deal for eased, tweened animations which all professional ads use. Flash calculates these at SWF compile time for much greater efficiency.)
In short, whatever way you do animation in HTML5 it's guaranteed to be: Higher bandwidth; more CPU intensive; harder to disable as it's built into the fabric of the page, not via an easily disabled plug-in.
Why does Steve hate Flash? Yes, there are performance concerns, but those could be addressed. The real reason is that it takes away Apple's gatekeeper status. Want to play a game on the iPhone? Go to the App Store. If Flash was there, anyone could make iPhone games, apps, etc of equal quality to most App Store apps but without the Steve approval process.
Popcap games on your iPhone? Say goodbye to 50%+ of those 59p game downloads that make up so much of App Store sales.