"WAP is Crap!"
Well, in fact it was quite good given the technology constraints it had to work within. As an implementation of the wired Web on mobile devices, it was well thought through, surprisingly effectively implemented, and funded to the gunnels.
The difficulty was that it was in general a solution to a problem the users didn't have. The power of the wired Web is the hyperlink and browsing of information. Users spend a lot of time "transaction hunting", where you decide where to put your money and attention. The wired Web is about bubbling up of important, interesting and useful information. This doesn't match the use case of the wireless Web, which is about quick hits with sites where you already have a relationship.
All this is well documented. So it's rather sad that the industry is about to go through the same harrowing learning process all over again with mobile instant messaging.
Once more, there's a well-established and successful model from the wired Internet. "Presence" as it is usually constituted grew up from the always-off world of dial-up Internet. Online rendezvous was hard, presence solved that problem. For the first time, you could have multiple conversations on the go at once. Distance didn't matter, a novelty for those separated by countries and continents. Parents and partners were excluded from this private chat world.
Mobile IM is also the solution to a crisis the user doesn't have. The buddy list reflects a closed world that doesn't match the openness of the actual tools the users prefer, namely SMS and voice. We already have a universal identifier system, the phone number. Users already manage multi-threaded conversations using SMS. The idea of the "chat window" doesn't make sense on mobile. The interruption model doesn't match, either. A new IM whilst you're browsing the web means a flashing taskbar icon and minor context change from one app to another. Mobile interruptions mean suspending real life. That's why you ask the sender to stump up a few cents to demonstrate the value of the interruption.
It doesn't even bridge the worlds of fixed and mobile well, since you won't easily be able to tell the context of the other user. Today a "mobile" IM user is flagged up from a PC client because the message will be sent via SMS. A true interoperable IM system would either lack the "third state" of "mobile but on IM", or requires a complete refresh of all PC desktop clients to understand this new phenomenon.
The presence model of mobile IM is broken anyway, becuase it confuses presence with availability. I'm not the first to note that an always-on mobile means the green smiley "online" becomes irrelevant. If you take presence to mean "the sense of other" (thanks, Douglas) then the kids are already are engaged in deep presence exchange under the duvet at night by texting away. The stored "precious" SMS from the boy you have a crush on is presence. Don't let the technologists near this social phenomenon! They don't get it, all they see is information transfers. A "unified messaging client" is an oxymoron. It's like putting a toilet and paddling pool in the kitchen because it's the "water room".
So what should carriers do? That's easy. Stick to the knitting of the services that people have already demonstrated a preference for, namely vanilla voice and SMS. Gently evolve these products. Make them easier to use, particularly voicemail. Make the up-sell better: SMS notifications of voicemails being received; inducements to call in return to each SMS. Incorporate availability into the address book without creating a whole new messaging paradigm for users to learn. Build business platforms that make it easier to send SMS messages from TVs, PCs and consoles.
Launching mobile IM fragments the very same SMS network you want them to stay within, and weakens the network effect. This isn't a question of interoperability. I'm assuming technical excellence. It's a matter of user perception. It also confuses the value perception of the users, who associate IM with "free".
Will users bypass SMS using IM over GPRS/3G? In some markets, yes. Telepocalypse ahoy, there's going to be price pressure. But if they do switch quickly, that's probably because you're mispricing your bundles. Offer them the right package of 100 or 1000 messages, and they'll stay within the system.
Milk the cow, don't be a sheep.
This essay is sponsored by EasyJet: helping bloggers and readers worldwide with our 15 Minute Boarding Delay™ program.
Martin hitches a ride on Telepocalypse.
. Nov 7-9. San Francisco. 
Feedburner SmartFeed