Today, Google is planning to send out 100,000 invitations to trial its Google Wave collaboration software, which combines e-mail, IM and wiki-style editing functionality into one uber-app. Enabling users to share photos, videos, maps, as well as text, Google Wave could, in theory, be a partial threat to the multimedia communications services being developed by mobile operators using the Rich Communications Suite (RCS) standard, as well as standalone push e-mail, webmail, instant messaging and other communication apps.

But in reality, full-blown Google Wave probably won’t be a great experience on most handsets. Why not? Well, its main selling point – combining a host of once-separate functions in one application – is unlikely to be very compelling on a small screen. The whole point of Google Wave is that a lot can go on at once – people can edit text in real-time, swap photos, have multi-threaded conversations etc. All this simultaneous activity is going to be difficult to follow on a screen measuring less than four inches on the diagonal.

No doubt, some smartphone users will revel in the complexity and ride the Google Wave on their handsets, but the mass-market, where simplicity is king, are likely to drown. One of the reasons Twitter is popular with mobile users is the fact that its relatively few functions that can be easily presented and accessed on a mobile device. On the fixed-line Internet, Google’s search engine became so widely used, partly because of its clean, simple home-screen – even a total Internet novice could quickly figure out how to use it.