One of the few companies in the valley that is going strong and in growth mode is AdMob where my friend Jason Spero is the VP of Marketing. Their ad statistics are always interesting (AdMob Metrics).
From the looks of things, their mobile ad plaform seems to still be gaining traction (traction is the most hideously overused word in the vc community right now by the way) as weaker competitors fall by the wayside. This seems to be a very classic story in ad companies where network effects accrue rapidly to the leader in a particular vertical once someone gets ahead. It will be interesting to see whether they can maintain this lead as the mobile market becomes less differentiated from the standard web.
That's not happening quite as fast as might be expected - especially overseas. The best mobile browsing device by a million miles is the iPhone but I suspect that even there the mobile browsing behaviors are makedly different than on the PC.
When you look at the other devices in the AdMob metrics report it is clear that there is still a ton of Openwave 6.x browsing going on (and other competitors in that class). It's not surprising if one considers the sheer number of devices with the Openwave browser - we were shipping over 100m copies per year of that thing in the middle of the decade and it's still being pumped out on a huge number of phones.
Number of devices is a dangerous metric however - there are only 3 or 4 million data subscribers on Verizon for example so even though everyone has a browser on their phone the "switched on" number skews heavily towards smart phones (the Moto RAZR is still the number one device for AdMob ads served but per-capita RIMM, Windows Mobile and Apple are dominant).
AdMob is also serving a lot of ads into iPhone applications providing a very nice alternative monetization scheme - you'll get a couple of orders of magnitude more distribution if you're a free app than a non-free app so shipping free and creating an ad-revenue stream is a great solution for many application categories especially entertainment and games. The only concern here is whether the business is moving "real" ads from brands or whether most of the ads are for other iPhone applications .. we saw that pyramid scheme in the FaceBook platform and that ended in disaster so hopefully that is not what is going on here.
The world now has five major smartphone operating systems - that's going to make for an interesting next few years but the competition will ultimately be great for consumers. How will it all pan out - that's the subject for another post (or series of posts).