What's the mobile killer app? After voice of course. This was the thorniest of the issues discussed at Silicon South-West's recent conference 'Wireless 2.0' in Bristol.

To Dr Tony Milbourn, founder of TTPCom, CEO of Camitri, and renowned developer of technologies which make wireless work, apps are what he called: "The soft, fuzzy stuff."

"What," asked Milbourn, "is the iconic application that makes things happen?"

Do people want the Swiss Army Knife or discrete functionality?"

Clearly the Swiss Army knife has not very good but many, adequate functions, while discrete devices can deliver superior performance.

Because of this dichotomy of user need, Milbourn came to the conclusion that: "The value in the phone is migrating to the very high end and the very low end."

David Wood, founder and executive vice president of Symbian, reckoned that a good operating system should cope with mobile phone performance issues, for instance, how to get: better battery life; more MIPs out of the CPU; more integration; a better user experience.

That being said, Symbian was only in 77m smartphones last year and clearly: "We want a killer app to drive buyer take-up," said Wood.

Wood had a number of these up his sleeve:

1. Access email via mobile phone. "There are 600m business email addresses but under 10 per cent have mobile access", said Wood..
2. Smart voice - voice routed through the corporate switchboard so one number gets the guy wherever he is.
3. Smart mobile access to maps with GPS showing routes, and with the ability to zoom in and out of maps and highlight the location of contacts. Plus a smart interpretation of the images generated explains what you're seeing.
4. Smart mobile access to the Web. Follow e-Bay auctions, access Facebook, YouTube etc.
5. Mobile content creation. Blogging at the Point of Inspiration. Take photos, upload comments. For instance the stories written in Japan for mobiles phone users called Keitai Shosetsu have attracted 25m users.

A problem in the West, according to Wood, is that the network operators discourage apps developers by insisting on taking too much of the return generated by new applications.

"DoCoMo takes a very modest share of the revenue from applications - say 10 per cent", said Wood, "Western operators like a much larger share and that drives developers out."

Eamonn O'Neill, Director of Postgraduate Research Studies in the Department of Computer Science at the University of Bath, also had a killer app. He reckoned the killer app is in supporting groups of people, rather than in the one-person-to-one-person interaction of today's mobile Internet.

"We need software allowing group interaction," said O'Neill.

Bath University has developed a sharing application called Cityware.

Steve Baker, Director of Software Platform Strategy at Motorola, had an equation for deciding whether an app's worth doing:

Utility > effort + risk

Where: utility = willingness to pay, and effort = everyone's effort

"The utility has got to outweigh the cost and the risk of that application," said Baker.

Having said that he took the view that: "It is balls-achingly difficult today to get applications out there."

"A number of mobile music services have been attempted and they don't seem to work in games Nokia tried n-gage and got out again" said Baker adding, "it's still a pain to access a Website on a mobile."

Android's top 50 applications include: social networking location-based services navigation messaging imaging payment and ticketing.

"There will be no application more iconic than voice that will drive handset sales, but there will be contagious applications. The potential lies in smaller, fragmented pockets of utility," said Baker, warning developers, "you need applications that span OSes, OEMs, and Operators. It's no good if an application is only available on my chip, or my OS, or my network."

See also: Mannerisms, the blog of David Manners. Updated twice daily, it's the distinctive, entertaining, authoritative and never dull commentary on the semiconductor industry, from someone who knows. Sign up for the Mannerisms eNewsletter.