The cellular industry has repeatedly attempted to port popular consumer services to the mobile environment. Internet became Mobile Internet. TV became Mobile TV. Despite the investment of billions of dollars in data networks, spectrum, devices, and marketing campaigns, very few services have ported successfully.

Yet digital music and podcasting prove that users will go to great lengths to mobilize entertainment, including actively connecting a media device to a PC and transferring to it content downloaded from the internet. But can podcasting become a cellular service enjoyed on handsets? Clearly, podcasting has certain attributes suitable for the mobile environment. First, it is an "on-the-go" experience. Second, enjoying audio content is not effected by the handset's small display screen. Thus should not a porting failure be construed as conclusive evidence that users simply do not believe that the mobile phone is a media device? This article outlines the critical issues that must be addressed if podcasting is to see even minimal mobile mass-market penetration.

Given the handset's small screen and the cumbersome browsing experience, how mobile users discover and receive podcasts will have a huge impact on the nature and success of the service. There are two alternative models: network-based solutions and client-based solutions. Network-based solutions like WAP offer podcast menus on the Operator's Portal. Users locate the appropriate podcast, and then initiate a download.

WAP has failed to appeal to the mass-market user. The click and wait, menu-intense experience of Mobile Internet is horrible. Few will navigate countless Portal menus to locate a podcast, and then wait for the download of a large file to end before listening to their podcast.

Podcasts can also be streamed off the Portal. Here, however, in addition to the cumbersome Portal-Pull issues, the user-experience becomes dependent on consistent and sufficient data transmission during the stream. A user listening to a podcast while commuting by train will often lose coverage altogether. Securing bandwidth in peak-hours or in congested areas is very difficult. Thus streaming can not deliver an acceptable level of service.

Whether downloaded or streamed, obtaining content via pull assumes that a user will regularly poll for content. Two problems: First, the active user concept runs counter to the Podcast model. Second, a compelling mobile experience must be simple and automated. The potential mass-market mobile user is not as "early-adopted" oriented as a current podcast user. Thus, the user-experience on mobile user must be as good, if not better than the iPod experience for the mass-market to accept it.

Client solutions reduce the amount of browsing and provide a more immediate, user-friendly experience. The first type of solution, offered by Odeo, involves a client that displays a catalogue-list of available podcasts. The user scrolls down the list and selects one, which initiates a content delivery session. Content discovery is simplified as WAP browsing to the portal is avoided. However, real-time delivery is required, which means consumption delays. Also, a consumption decision must be made daily.

The second client solution is that offered by MobiPod collaboration between Bamboo Mediacasting and Britcaster) and involves background download. Full version video and audio podcast files are delivered to the user transparently, without any user involvement required, for example overnight. Fresh content is available for immediate consumption for the morning commute with no network access required.

Will users willing to pay for mobile podcast services, and will operators actually want to launch anything but a barebones service for PR purposes?

People are clearly taking their entertainment with them. Also, working people have clearly definable windows of dead time while commuting to and from work. During these times, they are a captive audience. Will the mass-market, which holds mobile phones rather than other media-devices, be willing to adopt and pay for services which deliver personalized podcasts to them?

One barrier is the perception that podcasts are and should remain free. Whether users are willing to pay for podcasts on their mobile will depend of factors such as easy of use, quality of content, and price. If the user-experience is easy, it is quite likely that people will pay a small premium in order to receive Tier 1 content on their mobile phones, rather than buy an iPod and then bother with transferring content from their computer to a device each morning.

One thing is certain: the operator is keen to have such operator-provided services succeed. First, from a revenue perspective, operators subsidize the handsets, yet see no revenue when a user transfers music to it from the PC. Second, should the mass-market view iPod-like devices as their default device for media consumption, the mobile handset will be marginalized and become a voice-only device. As iPod develops Skype-like internet telephone functionality over WIFI, operators will lose voice as well. It is thus imperative for the operator that the mobile phone claim a firm stake as a media device.

Mobile podcasting, however, poses a few challenges to the operator. First, mobile networks are inefficient in terms of data transmission, and the cost to the operator of transmitting data is high. While a user might pay 20 Euro/month for unlimited residential broadband access, the same user might be charged 1 Euro/MB for mobile data. As the average 30-40 minute PC-based audio podcast is approximately 15 MB, the operator can not justify charging of a few Euros a month for a mobile podcast service, when a single Pull-downloaded video clip can generate two Euro.

Mobile podcasting be made more efficient. First, the size of podcasts can easily be reduced by simple content transcoding. A 30 minute podcast can be reduced to 1.5MB, without impacting sound quality. Furthermore, the delivery frequency of a podcast service can be reduced. (Delivering shorter podcasts is an option, but Tier 1 podcasters will not create "mobile-versions" of their programs unless it makes economic sense).

Second, the podcast files must be delivered during off-peak hours, ideally overnight. During peak hours and in congested areas, the cost of data delivery is at its highest. Delivery of large data files during peak hours will chill operator enthusiasm. Conversely, during off-peak hours, the network is empty, minimizing the cost of data transmission. This requirement would appear to point to a push service model, with scheduled off-peak delivery.

One final issue is that of billing and revenue. Mobile users will only adopt podcasting if the pricing structure is clear and reasonable. A transparent monthly subscription fee for the service, without any additional data charges, is mandatory. In terms of additional operator revenue potential, one point worth noting is advertising. As audio and video advertisements are easily included in podcasts, the potential for advertising revenue is significant.

To summarize, several key factors must be considered if mobile podcasting is to be even marginally successful. Usability issues are of paramount importance. Early adopters may occasionally pull content, but the mass-market will not. Rather, a client-based subscription push model appears to be the most suitable, both in terms of user experience and network utilization. In addition, a clear charging model is mandatory for user uptake. Finally, Tier 1 content, modified for the mobile experience, is important, yet relatively easy to secure. Now it remains to be seen whether attractive services are deployed and enjoyed.