Amongst other things, I chair the Mobile Industry Group for AIMIA. We recently launched the new Mobile Advertising Guidelines which try and just set some recommendations in place so that there is a common understanding on sizes (or rather ratios), purpose etc. While there has been some incredibly ill-informed press around on this (wondering why they aren’t government mandated, or complaining about lack of [audience] measurement in the guidelines), the mobile industry as a whole was pretty supportive of these as it makes it easier both for advertisers to start to see mobile as a valid channel and for mobile developers to know what ad sizes they are likely to be handling.

 It did, interesting, open up a can of worms on the ‘how many <?> in Australia?’. I asked around people in the mobile space with a good interest and understanding of this and here are some figures that seems to hold pretty well true.

Mobile subscribers: As at March 2009 (so only three months ago) we had the following:
Telstra          9.706m (41.7%)
Optus           7.634m (32.8%)
Vodafone      3.915m (16.8%)
Hutchison     2.036m (8.7%) 

Total: 23.219m which, if we assume a population of 20.9m, gives us mobile penetration of 111.4%.

Ok, next: how many iPhones (and who?). What follows are estimates, rumours, guesses and off-the-record comments. Surprisingly, in pulling these together from many sources, there was a large degree of similarity in the figures:
Telstra                120k (1.2% of customers) (18.5% of iPhones)
Optus                 350k (4.6%) (53.8%)
Vodafone           150k (3.1%) (23.1%)
Hutch & Virgin     30k (1.5%) (4.6%) 

Total             650k or about 2.8%. However, it also seems that up to 30% of access to mobile Internet sites, applications etc from Apple devices are from iPod Touches and estimates are that there are about 200k of these devices also access ‘mobile’ sites.

When you take into account that about 95% of these users access sites and apps on their phone on a daily basis - that, and the beautiful experience that can be provided on an iPhone (or Touch) makes for a very appealing audience.

NOTE: handsets and users of mobile content are not the same thing. The same sources quote figures of access to the mobile portal (content) and from there to the mobile web at:
Telstra/Sensis      2.3m
Optus                   0.6m
Vodafone             0.5m
Hutchison            1.6m

Just goes to show that when you engage your users with good content early in the piece (ie Hutch) you really get the benefit of them understanding the power of mobile.