Andrew Chen

A little late on this, but here are two more that I don't see in the comments...

- Comparison of the incentive funds of each platform
- Engagement potential with respective hardware constraints (shameless plug http://tinyurl.com/5sqofs)

Completely unrelated, but I was wondering whether your redesign / twitter header and so forth affected any of your stats?

actually they haven't ;-) It's been about the same, although Twitter does bring in some traffic. I think Twitter's useful for sure.

Lack of a payments platform for FB apps seems to be a pretty big difference

User demographics

Other questions to ask on the comparison include:
# Active Users
State of developer relations
Ease of getting started as a developer
Cost of developer tools (while everyone who is a developer will already own a PC, most will not own an iPhone, and what software will they need in which to program)

Usage Metrics: Facebook = started out as installs, progressed to monthly actives. iPhone = installs.

The difference being that the usage data is available for FB apps, but not for iPhones. For example, out of the 1M+ Tap Tap installs, what's the usage pattern? I, for one, played about 3 songs before deciding that it was boring and went back to playing Sudoku. Two weeks later, I discovered it was still on my phone and uninstalled it. But that kind of data isn't available.

It probably doesn't matter for paid apps, but for free apps, especially those hoping to monetize with the numerous iPhone ad solutions in the works, it could be important to know, but probably won't ever be.

you compelled me to write: http://okdork.com/2008/09/08/the-difference-bet...

Implementation options feels like it deserves a row. Facebook can use pretty much anything the web can use. I'm not sure, but I think that iPhone apps are limited to Objective C and javascript/dhtml on the web side.

IPhone supports location-based apps, where Facebook only supports MAYBE what city you're in (though the network or GeoIP).

Should there be a row that describes the difference between the "always in your pocket" nature of a phone app and the "when I remember to browse to it" nature of Facebook?

rows:
easy payment experience for consumers (ie: one click)
natural native gestures / UI
location information availability
always with you
offline availability

Developer Community: Apple: Strangled by NDA Facebook: ?Open & Supportive?
Audience: Apple: People who pay $200+ for cell phones & $60+/month service Facebook: Anyone with access to a computer with an internet connection.
Mobile Internet Penetration Among Userbase: Facebook: ? iPhone: 100%

Pricing should be broken out into developer cost vs. user cost, because a dev has to spend $99 for access to the app store. Other possible breakdowns

Coding language:
Facebook = anything like PHP/Ruby/Python/ASP/JSP
iPhone = Cocoa

Extra hardware:
Facebook = none
iPhone = Intel-based Mac running 10.5 Leopard (probably good to have an iPhone too)

Market Size:
Facebook = 100 million users
iPhone = 5 million activated phone (rough guess)

Market Size - potential and existing.
Cost to develop apps
Categories of popular apps (like solo vs. group as stated above.)
Platform (FB) vs. communications channel (iphone)
To previous commenter - iphone profiles http://www.louisgray.com/live/2008/09/iphones-m...
Crashability - FB= high, Apple = low. ;-)

Inspirational for the topic:
http://discussionleader.hbsp.com/haque/2008/08/...

I think they're different worlds of sorts because the iPhone apps provide all sorts of users and functionality on a mobile scale. It also brings the social aspect of Facebook apps to the mobile side and enhances it using location data.

The Facebook platform is also inherently more social than the iPhone platform because Facebook gives app developers access to their social graph. As a result, there seem to be more single-person apps like Labyrinth, Pandora, Tap Tap, etc. that are most popular on the iPhone vs. more social apps like Top Friends, Super Wall, Compare People, etc. that are most popular on Facebook.

As categories, I would say add "ease of development" and "opportunuties for viral platform distribution" or something like that