It will get bigger because the market will demand unified messaging - access to one mailbox from any client device, anywhere, at any time, and over any network. And after that it will probably start asking for multimedia messaging. At this time it is too early to tell if people will start sending digital postcards over the airwaves and the market for wireless video is way off. But Nokia is backing this one to the hilt and the Finns have a habit of being right when it comes to wireless futures. More attractive with GPRS, but the case for mobile e-mail clearly becomes more attractive when GPRS services are up and running.
Road warriors are then 'on line' all the time and e-mail comes in automatically.
Users in this environment are said to be in a 'remote' network. This means that transport mobility is not possible. The long-term solution to this problem is something called Mobile IP . Operators therefore have a lock on this market until the IETF nails down the IP Mobility spec - and the industry implements it. And the fact that operators have a very poor track record on the mobile data front is not encouraging.