AppleInsider took a look at AdMob (a mobile advertising and analytics provider) and concluded that...

Upgrade fee sees few iPod touch users updating to 3.0 software

AdMob's data indicates that 44% of iPhone users had upgraded (for free) to iPhone OS 3.0 by last week Saturday. However, only 1% of iPod touch owners had upgraded ($9.95 required for the iPod touch upgrade). They contrast this to the 78% of iPod touch owners who had upgraded to iPhone OS 2.0 sometime in 2008 (not just a few days after its release).

AppleInsider and AdMob conclude that this upgrade uptake difference is because of the $9.95 upgrade price. But, how do they explain the 78% uptake last year since the 2.0 upgrade also cost $9.95? I agree that cost is a big factor. But, I think the bigger factor is that most iPod touch owners do not have a strong reason to upgrade from what they see as an already fully functional iPod touch device. I finally got around to paying my $9.95 and updated my 1st generation iPod touch a few days ago.. And, I have to say that just getting the global search capability was worth the $9.95 for me. However, many iPod touch owners may not know enough about the value of search (or know but not consider it important for the way they use their touch) to pay and upgrade.

Whatever the case may actually be, this may send a signal to Apple that they need to release a new iPod touch soon and it needs to add some real value if they want to see this model progress in mindshare. I think the next iPod touch really needs at least camera, probably a microphone and perhaps a GPS (though that would be problematic without 3G).